S/Na2S S2 2- Na2S/Na2SO3

Transcript

1 ω ω ω Η Δ δ τορ ή Δ τρ ή " ", 2016

2 Η Ω Ω Ω Η Η Η Η Η Ω Ή ω ω Η Ε Ε Ε :., -,. (Ε ω ).., -,.., -,.., -,.., -,.., -,..., -,.

3 ί -.,..,,,.,.....,.,..,,..,,..,...,.,.,.,.,.,.,.,...,.

4 ί.,. Έ.., -.,, /,.,. Ω TiO2.,., (S/Na2S Na2S/Na2SO3)., S/Na2S S2 2-., Na2S/Na2SO3. Ω TiO2

5 (CuS, CoS, Cu2S).,, TiO2 WO3 BiVO4..

6 Abstract The aim of this study was the photoelectrochemical production of electricity and hydrogen using Photo-fuel cells. Photo-fuel cells are basically photoelectrochemical cells which can be used as an alternative way to convert solar energy into useful forms of energy photo-degrading simultaneously organic or inorganic wastes which are used as sacrificial agents. The basic configuration of such a cell comprises of a photoanode which is a light-absorbing semiconductor electrode and of a counter electrode in which an electrocatalyst is deposited. The two electrodes are immersed in an aqueous electrolyte solution which contains the sacrificial agent and are connected through an external circuit. When the photoanode is irradiated with photons that have energy equal to or higher than the band gap of the semiconductor, electron-hole pairs are created. The photo-generated holes in the valence band diffuse to the semiconductor-electrolyte interface where they oxidize the sacrificial agent, while the electrons are transferred through the external electrical circuit to the counter electrode and they take part in reduction reactions. In the case of Photo-fuel cells using organic sacrificial agents, ethanol was studied as a representative example of alcohols that can be found in different kind of wastes and biomass by-products. TiO2 was used as photo-anode both sensitized and non-sensitized in the visible spectrum with different kind of quantum dots. Also, alternative electrocatalysts were studied in order to subsistute platinum. Apart from the different kind of organic sacrificial agents, there are also inorganic coumpounds that can be used as very efficient hole acceptors, enabling the effective separation of the charge carriers. In the present study, two different sulfur mixtures were used (S/Na2S and Na2S/Na2SO3), high amounts of which are released from fossil fuel processing. In the first case, only electricity production was studied due to the fact that the photoelectrocatalytic efficiency of H2 production is very low in solutions containing only sulfide ions. This is attributed to the formation of disulfide ions, S 2- which exhibit a less negative reduction potential than protons. In the case of Na2S/Na2SO3 mixture, both photoelectrochemical electricity and hydrogen production were studied. TiO2 was again used as photo-anode combined with different quantum dots whereas in that case metal sulfides (CuS, CoS, Cu2S) were studied as electrocatalysts because platinum is unstable and increases the charge carrier transfer resistance in the presence of sulfur mixtures.

7 Finally, for the photoelectrochemical production of hydrogen, in addition to TiO2, WO3 and BiVO4 were synthesized and studied as well. These materials are medium band gap semiconductors which exhibit better photocatalytic activity than titania due to their visible light absorption.

8 ό Ε ω : Κ 1: Ε ω ω ω Ά Fermi (Fermi Level) TiO TiO Κ 2: ω /

9 ph Κ 3: Π TiO TiO WO BiVO Pt Pt FTO FTO ΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙ

10 3.5.2 (IPCE) (SEM) Π (X-ray diffraction, XRD) Π Κ 4: Φω ω ω ω ω X TiO TiO2 Π (UV-Vis DRS) CdS/TiO2 UPS GMC-S-X XPS GMC-S-X ( )

11 TiO Κ 5: Φω ω ω ω ω ω (DRS)ΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙ..ΙΙΙΙ Raman Cu2S Π CdS CdS/TiO TiO ZnS/CdSe/CdS/TiO Κ 6: Ε ω ω ω WO3 BiVO

12

13 ή ί ί ή ί ή 1: ή ( Km 2 ) ά ί ϊ ά ή ό % ή ή ύ ί 20 TW [1]

14 1. ό ό ύ ή., (, ), [2]. 56% ( ) , US Energy Information Administration (US-EIA) [3] ( 1)., (,, ) 85% [4],. ή 2: ό ώ ά έ έ [3]

15 2. ώ έ έ.,. ( ) (United States Environmental Protection Agency) [5].,,..,., [6,7]., [8]. ( ). : Ε :. Η Θ. ( )

16 Υ Ε :. (,,,, ).,. ω Ε :,.. ( ). :, ( ).. (,,..) (,..). Η :.,..,

17 3. ή έ ί ή 3β10 24 J, [9,10]., TW, ( 3),. ή 3: ά ή ί. 2012, 7 18 TW [11].,,., [12]. Π

18 ί : ή ί ά ό έ ό ά ί ώ ώ [1]. ή έ ύ TW) ή Α σ - % ς Α 4 ς ς σ ς. Υ 1-2 Τ ς, TW. Γ ω 12 Μ σ σ. Α σ σ Π 10 ς ς GW/ ώ ς. Ε ό ό 10 Α % ς ς ς ς. Α, % ς Η >20 ς ς ς ϊ σ σ σ ς %. Έ 20 TW, 10% m 2 900x900 m 2 ( 1) [1].,.,,. (Solar-Thermal System). Έ.,,

19 (Photovoltaic Systems).,, % [13]. (Photoelectrochemical Systems),,.,., 1839 Edmund Becquerel ω ( ) [14] Fujishima Honda [15].. Ό,,. ( ),., [16].,,

20 ,. /..,. ό ή.,

21 ί [1] R. van de Krol, M. Grätzel, Photoelectrochemical hydrogen Production, Electronic Materials: Science & Technology, Springer, [2] J. K. Casper, Fossil Fuels and Pollution: The Future of Air Quality, Facts On File, New York, [3] US Energy Information Association (US-EI ): [4] M. I. Hoffert, Farewell to fossil fuels? Science, 2010, 329, [5] United States Environmental Protection Agency: [6] N. L. Panwar, S. C. Kaushik, S. Kothari, Role of renewable energy sources in environmental protection: A review, Renewable and Sustainable Energy Reviews, 2011, 15, [7] I. Dincer, Renewable energy and sustainable development: a crucial review, Renewable and Sustainable Energy Reviews, 2000, 4(2), [8] έ ώ ώ ό έ : [9] A. Fujishima, D. A. Tryk, Energy Carriers and Conversion Systems: vol. I, Photochemical and Photoelectrochemical Water Splitting. In: Encyclopedia of Life Support Systems, T. Ohta and T. N. Vezirozeu (Eds.). ELOSS & UNESCO. [10] C. A. Grimes, O. K. Varghese, S. Ranjan, Light, Water, Hydrogen: The Solar Generation of Hydrogen by Water Photoelectrolysis, Springer Science + Business Media, LLC, New York, [11] International Energy Statistics: [12] N. S. Lewis, D. G. Nocera, Powering the planet: chemical challenges in solar energy utilization. Proc. Nat. Acad. Sci., 2006, 103, [13] T. M. Razykova, C. S. Ferekides, D. Morel, E. Stefanakos, H.S. Ullal, H.M. Upadhyayae, Solar photovoltaic electricity: Current status and future prospects, Solar Energy, 2011, 85(8),

22 [14] E. Becquerel, Recherches sur les effets de la radiation chimique de la lumiere solaire au moyen des courants electriques, Comptes Rend. Acad. Sci., 1839, 9, [15] A. Fujishima and K. Honda, Electrochemical photolysis of water at a semiconductor electrode, Nature, 1972, 238, [16] A. Heller, Conversion of sunlight into electrical power and photoassisted electrolysis of water in photoelectrochemical cells, Acc. Chem. Res., 1981, 14,

23 ά 1 ή ί ώ ή 1.1: ό ά έ ύ ώ ό ά ά ά ύ [1]

24 1.1 ά ά ώ..,,,. Ό,. ( Π cm -3 ).,,., ( 1.2).,. (Valence band, VB)

25 ή 1.2: ό ώ ώ ό ί ύ ό [2]. ω (Conduction band, CB)., ( nergy band gap, Eg) [3]: Ε = E E V ev (1.1)..,.,.,.,,

26 .. (Eg > 4 ev), ω (insulator)., ω (conductors).,. ω (Semiconductors),.,, ( ) [4,5]., ή 1.3: έ ώ ό ά έ, ύ ύ

27 1.2 ί ώ 1.2. Ά έ ί,. ω (direct semiconductor).,.,,, k [6]. ω (indirect semiconductor).,. (defect energy state) [7] ί ί ί. Έ,, ω (Intrinsic semiconductor). Si, Ge InAs, SiC, GaAs [3]. ω ω (Extrinsic semiconductors) ω ω, TiO2, ZnO NiO. Έ ( ),,

28 . -n -p. ( -n ),,., -p [4]..,., -.,,., [8,9]. 1.3 ί Fermi (Fermi Level).,. Fermi Fermi (Fermi energy level), ½.. Fermi,., Fermi ( 1.4).,, Fermi

29 . n-, Fermi, p- Fermi ( 1.4). ή 1.4: έ έ Εκχςξ έ ώ ό έ ή ό ή ό ύ n ύ p. 1.4 έ ώ ώ έ ά,. e - h + Φ.,,

30 ., y e - ( ) (Normal Hydrogen electrode, NHE). + / 2 4,5 ev., ph., -59 V ph : =. (1.2) 1.5. ή 1.5: έ ώ ώ ά ύ ή ό ύ ph=1 ά ά έ ά [10]

31 1.5 έ ύ ό ό Ό,.., : (1.3) Planck. (threshold wavelength),, : = = (1.4), (h + ): Ημιαγωγ ς h + h +,. Έ, e - h +. Έ,.,., - [2,11] Πn Πp

32 ή 1.6: ή ί ύ ί - ή ά ύ/ ύ ό ύ n ί ί ύ p ί ώ [12]. 1.6 ό ώ ώ. : (1), (2), (3), (4) (5) [13,14].,.,, TiO2,

33 Si ( 1.5) 1., 1 3 ev Φ (Eg>2.2 ev)., (Eg>1.0 ev).,. ή 1.7: ά ύ ό AM 1.5 έ ό ά ύ [15]. 1 ΑΜ 1.5: αφο ά σ ο ια ό φ ς ό ς α ό α α ί αι σ ιφά ια ς ς αι αφού ο φ ς ια ά ι ο ιά ή ο ς 1.5 φο ές ο ά ος ς α όσφαι ας [16]

34 .. [17].,, /..,. Ό,, /..,. Έ,, (.. TiO2, ZnO), (.. CdS, ZnS) (.. Ge3N4).,. n-, TiO2, WO3, SrTiO3, ZnO ZnS,..,.,, CdS, PbS

35 CdSe.,,. p-,, [18]. 1.7 TiO2 ό έ ί, TiO2.,,. Έ,. -n, (anatase), (rutile) (brookite) ( 1.8). TiO2. [19] 700 όc., [20]. Π 1.1. TiO2, [21-23]

36 ή 1.8: έ έ TiO2: A) ή (a=b= 4,5937 Å, c= 2,9581 Å), ί (a= 9,16 Å, b= 5,43 Å, c= 5,13 Å), ά (a=b= 3,7842 Å, c= 9,5146 Å) [24,25]. ί 1.1: έ ό ώ ώ ά ί [2], [26]. g (ev) ECB (V vs NHE, ph=0) EVB (V vs NHE, ph=0) ά ή

37 2.,.,, [27]. TiO2, silica gel,,,, [28-30].. TiO2,,,,., TiO2, Φ. (chemical vapor deposition), (hydrothermal deposition), - (sol-gel method) [31-34].,,. (electrodeposition), (dip coating), doctor blading spin coating TiO2. 2 Ως ο ής α α ί αι φ ο α ά σ ό ο ο α α ύ ς β ίσ αι σ σ ά ο φή αι ο φ ο α α ό ο σύσ α ί αι σ ή ή αέ ια φάσ

38 TiO2 Degussa P-25 3:1. Degussa P-25 Π 1.2.,, [2]. Degussa P-25. ί 1.2: έ έ ό ά, ί ά έ Degussa P-25 [35]. BET surface are (m 2 /g) Ό ό (cm 3 /g) Μέ ά ό (nm) ά ή Degussa P

39 1.8 ή ά TiO2 TiO2 [15, 36, 37]. Ό, TiO2,,. : έ TiO2: io + hv e + + h V 1.9 TiO2 -.,. ή.9: ό ί ύ ί - ή έ έ ί TiO2 ό ύ ό ά [38,39]

40 ϋ CO2 H2O. ( ϋ) (2.80 V) [38,39]. : h + V + CO + O h + V + O O + + ΟΗ + CO + O Ό.,, 2 - HO2 H2O2 [40-42]. - [27,43]: e + Ο Ο Ο + ΟΗ ΗΟΟ ΗΟΟ + e O OO + + O

41 ί [1] A. Kudo and Y. Miseki, Heterogeneous photocatalyst materials for water splitting, Chem. Soc. Rev., 2009, 38, [2]., /,,, [3] N. Arora, Review of Basic Semiconductor and pn Junction Theory, MOSFET Models for VLSI Circuit Simulation Computational Microelectronics, Publisher Springer, Vienna, pp 15-68, [4] D. A. Neamen, Semiconductor Physics and Devices: Basic Principles, Chapter 3: Introduction to the Quantum theory of solids, 4th Edition, McGraw- Hill, New York, [5] B. V. Zeghbroeck, Principles of Semiconductor Devices, e-book of Electrical and Computer Engineering Department of University of Colorado at Boulder, [6] J. Allison, Electronic Engineering Semiconductors and devices, McGraw-Hill, Shoppenhangers Rd Maidenhead Berkshire England, [7].. ό, ή ό ό ώ ώ ί ύ ί CdSe, ή ί ή ό ώ ώ ώ ύ ό ί, [8] N. M. Ravindra, V. K. Srivastava, Technical note: Temperature dependence of the energy gap in semiconductors, Journal of Physics and Chemistry of Solids, 1979, 40(10), [9]. ύ, έ έ ώ ώ έ έ, ή ή, ή ώ,. [10] M. Grätzel, Review article: Photoelectrochemical cells, Nature 414, 2001, [11]. L. Linsebigler, G. Lu, and J. T. Yates, Photocatalysis on TiOn Surfaces: Principles, Mechanisms, and Selected Results, Chem. Rev. 1995, 95, [12] I... Hassan, Solar Energy Conversion by Photoelectrochemical Processes, PhD thesis, University of Bath,

42 [13] R. A. Al-Rasheed, Water Treatment by Heterogeneous Photocatalysis: A Review, In Proceedings of the 4th SWCC Acquired Experience Symposium, Jeddah, Saudi Arabia, [14] R. van de Krol, M. Grätzel, Photoelectrochemical hydrogen Production, Electronic Materials: Science & Technology, Springer, [15] A. Fujishima, T. N. Rao, D. A. Tryk, Titanium dioxide photocatalysis, J. Photochem. Photobiol. C: Photochem. Rev., 2000, 1, [16].. ά, ϊ ά ή, ό ή, 2007, ί. [17] D. Bahnemann, A. Henglein, J. Lilie and L. Spanhel, Flash photolysis observation of the absorption spectra of trapped positive holes and electrons in colloidal titanium dioxide, J Phys. Chem. 88 (1984) 709. [18] K. Triantafyllidis, A. Lappas, M. Stöcker, The Role of Catalysis for the Sustainable Production of Bio-fuels and Bio-chemicals, 1st Edition, 2013, edited by Elsevier, Amsterdam, The Netherlands. [19] A. I. Kokorin, D. Bahnemann, Chemical Physics of Nanostructured Semiconductors, VSP:Boston, MA, USA, [20] O. Carp, C. Huisman and A. Reller, Photoinduced reactivity of titanium dioxide, Progress in solid state chemistry, 2004, 32, [21] R. I. Bickley, T. Gonzalez-Carreno, J. S. Lees, L. Palmisano, R. J. D. Tilley, A structural investigation of titanium dioxide photocatalysts, Journal of Solid State Chemistry, 1991, 92(1), [22] A. Di Paola, G. Cufalo, M. Addamo, M. Bellardita, R. Campostrini, M. Ischia, R. Ceccato, L. Palmisano, Photocatalytic activity of nanocrystalline TiO2 (brookite, rutile and brookite-based) powders prepared by thermohydrolysis of TiCl4 in aqueous chloride solutions, Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2008, 317(1 3), [23] D. C. Hurum, A. G. Agrios, K. A. Gray, T. Rajh, M. C. Thurnauer, Explaining the Enhanced Photocatalytic Activity of Mixed Phase TiO2 Using EPR, J. Phys. Chem. B, 2003, 107,

43 [24] J. Moellmann, S. Ehrlich, R. Tonner and S. Grimme, A DFT-D study of structural and energetic properties of TiO2 modifications, J. Phys. Condens. Matter, 2012, 24, (8pp). [25] M. Landmann, E. Rauls and W. G. Schmidt, The electronic structure and optical response of rutile, anatase and brookite TiO2, J. Phys.: Condens. Matter, 2012, 24, (6pp). [26].,,,, [27] H. Dong, G. Zeng, L. Tang, C. Fan, C. Zhang, X. He, Y. He, An overview on limitations of TiO2-based particles for photocatalytic degradation of organic pollutants and the corresponding countermeasures, Water Research, 2015, 79, 128Π146. [28] M. Langlet, A. Kim, M. Audier, J. M. Herrmann, Sol-Gel Preparation of Photocatalytic TiO2 Films on Polymer Substrates, Journal of Sol-Gel Science and Technology, 2002, 25(3), [29] X. Wang, Z. Hu, Y. Chen, G. Zhao, Y. Liu, Z. Wen, A novel approach towards high-performance composite photocatalyst of TiO2 deposited on activated carbon, Applied Surface Science, 2009, 255(7), [30] S. Sfaelou, V. Dracopoulos, P. Lianos, Quantum-dot sensitized Solar Cells with Metal Electrodes, Journal of Advanced Oxidation Technologies, 2014, 17(1), [31] S. K. Dong, S.-Y. Kwak, The hydrothermal synthesis of mesoporous TiO2 with high crystallinity, thermal stability, large surface area, and enhanced photocatalytic activity, Applied Catalysis A: General, 2007, 323, [32] Y.-C. Liu, Y.-F. Lu, Y.-Z. Zeng, C.-H. Liao, J.-C. Chung and T.-Y. Wei, Nanostructured Mesoporous Titanium Dioxide Thin Film Prepared by Sol-Gel Method for Dye-Sensitized Solar Cell, Hindawi Publishing Corporation, International Journal of Photoenergy, 2011, Article ID: , 9 pages, doi: /2011/ [33] K. Nagaveni, M. S. Hegde, N. Ravishankar, G. N. Subbanna and G. Madras, Synthesis and Structure of Nanocrystalline TiO2 with Lower Band Gap Showing High Photocatalytic Activity, Langmuir, 2004, 20 (7),

44 [34] C. Su, B.-Y. Hong, C.-M. Tseng, Sol gel preparation and photocatalysis of titanium dioxide, Catalysis Today, 2004, 96(3), [35] Zebao Rui, Shangren Wu, Chao Peng, Hongbing Ji, Comparison of TiO2 Degussa P25 with anatase and rutile crystalline phases for methane combustion, Chemical Engineering Journal, Volume 243, 1 May 2014, Pages [36] U. I. Gaya, A. H. Abdullah, Heterogeneous photocatalytic degradation of organic contaminants over titanium dioxide: a review of fundamentals, progress and problems, J. Photochem. Photobiol. C: Photochem. Rev. 2008, 9, [37] K. Nakataa, A. Fujishima, TiO2 photocatalysis: Design and applications, Journal of Photochemistry and Photobiology C: Photochemistry Reviews, 2012, 13, [38] R. Liang, A. Hu, M. Hatat-Fraile, N. Zhou, Nanotechnology for Water Treatment and Purification, Chapter 1: Fundamentals on Adsorption, Membrane filtration and advanced oxidation processes for water treatment, edited by A. Hu and A. Apblett, Springer 2014, Switzerland. [39] 0. Legrini, E. Oliveros and A. M. Braun, Photochemical Processes for Water Treatment, Chem. Rev., 1993, 93, [40] M. Umar and H. Abdul Aziz, Chapter 8: Photocatalytic Degradation of Organic Pollutants in Water, Book: Organic Pollutants - Monitoring, Risk and Treatment, edited by M. Nageeb Rashed, 2013, [41] M. N. Chong, B. Jin, C. W. K. Chow, C. Saint, Recent developments in photocatalytic water treatment technology: A review, Water Research, 2010, 44, [42] J. Schneider, M. Matsuoka, M. Takeuchi, J. Zhang, Y. Horiuchi, M. Anpo and D. W. Bahnemann, Understanding TiO2 Photocatalysis: Mechanisms and Materials, Chem. Rev., 2014, 114 (19), [43] M. R. Hoffmann, S. T. Martin, W. Choi, D. W. Bahnemann, Environmental Applications of Semiconductor Photocatalysis, Chemical Reviews, 1995, 95,

45 ά 2 έ έ ώ ώ ή 2.1: ό ά ύ ύ [1]

46 ή,, ( ) ( ),. ( ).,.,., [2]. ( 2.2).,,., -., / H + H2., [3]

47 ή 2.2: ή ά ύ ύ ί ί ό ώ ά ά ό έ ύ. 2.1 ά ά ά ύ (0 V vs. NHE ph=0)

48 2 2 (1.23 V vs. NHE ph=0) ( 2.3)., 1.23 ev. ή 2.3: έ έ ώ έ ό ό ύ ί ά ύ [4]. (1.23 ev) ( ev) [5] ( ev) [6]., 1.9 ev, 650 nm. 2.4.,,., CdS CdSe. S 2- Se

49 [7]: Cd v e + + h V + Cd + h V Cd + +S ή 2.4: ό ά έ ύ ώ ό ά ά ά ύ [8]., : + + +, + +, E o o o E = +. V vs. N E =. V vs. N E, : , + +, E o o o E = +. V vs. N E = +. V vs. N E

50 Gibbs : =. : : : Faraday : (T=298 K, C= 1mol/L P= 1bar),, Gibbs = / ή 2.5: ό ί ί ί ό ώ ά έ ό ί έ ύ ί ό ά [9]

51 2.2 ά ά ή ό ώ Έ.., (sacrificial agents) e -, -., O2, [10,11]., H2. Ω [7].,. ω (Photo-fuel cells) έ ό ώ [12-16]

52 ,,... / ( ) CO2 2 ( Ο2) CO2 H2O ( O2) [17]: ί : C O + κ z O κco + κ z + λ ί : C O + κ + O κco + λ O ( 2 -, 2,, 2 2). - (photo-reforming)., ( G = 237 J/mol), Gibbs. e -. - e -. - TiO2 CO2. Ό, 2,.,. / ( ) : Η Ο + h + O + + O + h + O

53 .,.. TiO2, ( ).., CdSe TiO2 S 2- /SO3 2- S2/S2 2-.,,. Π 2.1., : + + Ό, CO2., ph. ph, + ( ) 2 ( V )., ( OH - ), OH - ( V). (V )., -.,

54 3 2 : + + Ό, ( VIII IX). ί 2.1: ά ί ί ί ύ TiO2 ό ό έ [12]. Φω : h TiO 2 e h (I) e - 2 ( ) : O O HO HO H O OH OH (II) e + H e + H e : C2H5OH + 3H2O + 12h + 2CO2 + 12H + ( ph) (II ) OH - + h + OH C2H5OH+12OH 2CO2 + 9H2O ( ph) (IV) : C2H5OH+2h + CH3CHO+2H + C2H5OH+h + C2H5O +H + (V) Κ ph (0.00 V ph=0) 2H + + 2e - H2 ph (-0.77 V ph=13) 2H2O + 2e - H2+2OH - (VI) (VII) ph (1.23 V ph=0) 2H + +½ O2 + 2e - H2O (VIII) ph (0.46 V ph=13) H2O+½ O2 + 2e - 2OH - (IX) ( ) 2 (ethanol reforming): C 2H 5OH + 3H 2O 2CO 2 + 6H 2 2 (ethanol mineralization): C 2H 5OH + 3O 2 2CO 2 + 3H 2O (X) (XI)

55 2.2.2 ό ό ώ,. : H2S, S 2Π /SO3 2-, Br Π, I Π, CN Π Fe 2+. S, S 2- SO3 2-,. ( S 2- /SO3 2- ). Έ S 2- / SO3 2-.,. Έ CdS/TiO2, Cd 2+ S 2- CdS [10].,, S/Na2S Na2S/Na2SO3., S 2- S2 2- S 2-. : + + +, S2 2-. Ό S 2- /SO3 2-, SO3 - (

56 ). SO3 2- SO4 2- S2O6 2- : ή S 2- Na2S, S2 2- SO3 2- : , S2 2- [10, 18, 19]. 2.3 ά ύ/ ύ ό ί Ό,.. ph, / /

57 Ό, H + OH -. : Μ ΟΗ k O + + a + Μ ΟΗ + k + a O ph ( 2.6).,,,. ph (point of zero charge, pzc) [20]. ή 2.6: έ ή ί ί έ ά TiO2 ί ύ ύ ί ά ph ύ. pzc TiO2 ί 6.0 ± 0.2 [20-22]. e - ( h + ). Ό, /., Fermi Fermi. (e - n- h + p

58 )., Fermi n- (. Fermi ) e -.,, e -, (depletion layer, DL) ( 2.7) [9]. ή 2.7: ί ά ά n- ύ ό ό έ ή ά ύ [23]. (Space Charge layer (SCL)). 2.7 [23,24]., /.,. Helmholtz Helmholtz (Inner Helmholtz plane (IHP)) e - /

59 , Helmholtz (Outer Helmholtz plane (OHP)) ( 2.8). Helmholtz ( 2-5 Å),, Å., Gouy-Chapman 30 nm. w Helmholtz [26, 26]., Csc, CH CG, Helmholtz Gouy-Chapman [20, 23]. ή 2.8: ό έ ά Helmholtz ί ά ύ/ ύ. ό ί Helmholtz (IHP) ί ό ό + - έ ά ύ ό ί Helmholtz (OHP) ά έ έ ό [9]

60 2.4 ά ύ ύ έ ό ή - (I-V curves)...,.,,. ω (short circuit current, ISC).,, (open circuit potential, VOC). Έ (Pmax) -, Pmax= ( V)max

61 ή 2.9: ύ ύ ά ό ύ ύ ά ό ό.. (Fill Factor, FF). : F. F. = V x SC V OC., 0 1 ( )

62 . (efficiency, n) (Pin) : n% = V x i % = x i %. (quantum efficiency),..,. 0, 1.,, 1.,, 0., ( 2.10).,

63 ή 210: ή ή ύ ή ό ό ύ ύ.,. ω (External Quantum Efficiency). (Incident Photon to Current Efficiency, IPCE) : =. Ό, : : :

64 ω (Internal Quantum Efficiency). (Absorbed photon-to-current Efficiency, APCE). APCE IPCE : = =. Ό A, R, T (Absorption), (Reflectance) (Transmission)., (Solar to Hydrogen Efficiency, STH%) : % =. %. Ό J, P 1.23 V ( ph=0).. Ό,

65 ή 2.11: ά ά ό ό ή ό STH Efficiency) ό ύ ή ύ ά ά ό ά ί ώ ώ ό ί ί. mw/cm 2 ) [27]

66 2.5 ά ά ό ό ύ ύ,. ph ά.,. [28]. : O + λ κ h+ η ε τρο της κ / a + λ O Gibbs [9] ph, ph.,

67 ph, Φ [29]., ph. Ό, ph 0. pzc TiO2 [21],. Ό ph (ph>pzc) ph pzc (ph<pzc) [29,30]., < : io + + io +, p T 2 + =. > : io + O io + O, p T =., ph [31] ί.,., 80 C. 80 C, 0 C [29]., 20 C - 80 C [32].,

68 ,. 2.6 Μέ ί ή ά TiO2.. Έ.,, [24]., /. Έ. /.,. (Highest Occupied Molecular Orbital, HOMO) (Lowest Unoccupied Molecular Orbital, LUMO) [33,34]., [35], [36], [37].. ( 2.12) [38]

69 ή 2.12: ή ά ώ ώ ά ά ύ ύ ύ [39]. doping,, [9]. doping e -, e - [40,41]. doping TiO2 Cu, Ni, Co, Fe, Mn, Cr, Au, Ag, Pt [42-44]. Ω,. TiO2 TiO2 ( 2.13). Φ, e -.,

70 [45].., C, N, B, P, F, I TiO2 [46,47]. Ό, ( 2.13). doping., 2 [48]. 1-2%, cm -3. [9]. ή 2.13: ό ά TiO2 ί doping (hv1) ό ί έ hv2 έ hv3) [49]

71 Έ TiO2, [50]. TiO2 [51]..,, e -., TiO2 Η Θ e - [52]., (Quantum Dots) [51].,, [53-55]

72 ή 2.14: ά ί έ ύ ώ ώ ύ έ. ί έ ί ί : ΒιΣ σς, ΒιΣκ σς, ΒιΤκ. σς, ΟηΣ. σς, ΟηΣκ. σς, Sb2S3 σς, Ση2Se3 σς [56]. Έ TiO2 CdS n- Eg= 2.4 ev., CdS/TiO2,., e - CdS., TiO2, e - TiO2 CdS., ( 2.15)

73 ή 2.15: ό ά ό ί TiO2 έ ί CdS ί ά ί ά ό ύ ύ., [57,58]. Ό, TiO

74 ί [1] C.-H. Liao, C.-W. Huang and J. C. S. Wu, Hydrogen Production from Semiconductor-based Photocatalysis via Water Splitting (Review), Catalysts, 2012, 2, [2] J. Li, N. Wu, Semiconductor-Based Photocatalysts and Photoelectrochemical Cells for Solar Fuel Generation: A Review, Catal. Sci. Technol., 2015, 5, [3] D. Wei and G. Amaratunga, Review paper: Photoelectrochemical Cell and Its Applications in Optoelectronics, Int. J. Electrochem. Sci., 2007, 2, [4] M. Kitano and M. Hara, Heterogeneous photocatalytic cleavage of water, J. Mater. Chem., 2010, 20, [5] M. F. Weber, M. J. Dignam, Splitting water with semiconducting photoelectrodes-efficiency considerations, Int. J. Hydrogen Energy, 1986, 11, [6] J. R. Bolton, S. J. Strickler, J. S. Connolly, Limiting and realizable efficiencies of solar photolysis of water, Nature, 1985, 316, [7] J. Schneider, T. A. Kandiel, D. W. Bahnemann, Solar Photocatalytic Hydrogen Production: Current Status and Future Challenges, Chapter in Materials and Processes for Solar Fuel Production, Volume 174 of the series Nanostructure Science and Technology, 2014, pp [8] A. Kudo and Y. Miseki, Heterogeneous photocatalyst materials for water splitting, Chem. Soc. Rev., 2009, 38, [9] R. van de Krol, M. Grätzel, Photoelectrochemical hydrogen Production, Electronic Materials: Science & Technology, 2012, Springer. [10] J. Schneider and D. W. Bahnemann, Undesired Role of Sacrificial Reagents in Photocatalysis, J. Phys. Chem. Lett., 2013, 4 (20), [11] T. Kawai, T. Sakata, Conversion of Carbohydrate into Hydrogen Fuel by a Photocatalytic Process, Nature, 1980, 286,. [12] P. Lianos, Production of electricity and hydrogen by photocatalytic degradation of organic wastes in a photoelectrochemical cell: the concept of the

75 Photofuelcell: a review of a re-emerging research field, J. Hazard Mater., 2011, 185(2-3), [13] M. Kaneko, J. Nemoto, H. Ueno, N. Gokan, K. Ohnuki, M. Horikawa, R. Saito, T. Shibata, Photoelectrochemical reaction of biomass and bio-related compounds with nanoporous TiO2 film photoanode and O2-reducing cathode, Electrochem. Commun., 2006, 8, [14] M. Antoniadou, P. Lianos, Photoelectrochemical oxidation of organic substances over nanocrystalline titania: Optimization of the photoelectrochemical cell, Catal. Today, 2009, 144, [15] A. Patsoura, D. I. Kondarides, X. E. Verykios, Photocatalytic degradation of organic pollutants with simultaneous production of hydrogen, Catal. Today, 2007, 124, [16] P. A. Mandelbaum, A. E. Regazzoni, M. A. Blesa, S. A. Bilmes, Photoelectrooxidation of alcohols on titanium dioxide thin film electrodes, J. Phys. Chem. B, 1999, 103, [17] I. Rossetti, Review article: Hydrogen production by photoreforming of renewable substrates, ISRN Chem. Eng., 2012, Article ID: , 21 pages, doi: /2012/ [18] N. Buhler, K. Meier, J. F. Reber, Photochemical Hydrogen-Production with Cadmium-Sulfide Suspensions. J. Phys. Chem., 1984, 88,. [19] H. K. Jun, M. A. Careem, and A. K. Arof, A Suitable Polysulfide Electrolyte for CdSe Quantum Dot-Sensitized Solar Cells, Hindawi Publishing Corporation, International Journal of Photoenergy, 2013, Article ID: , 10 pages, [20] R. Beranek, Review Article: (Photo)electrochemical Methods for the Determination of the Band Edge Positions of TiO2-Based Nanomaterials, Hindawi Publishing Corporation, Advances in Physical Chemistry, 2011, Article ID: , 20 pages, doi: /2011/ [21] T. Preocanin and N. Kallay, Point of Zero Charge and Surface Charge Density of TiO2 in Aqueous Electrolyte Solution as Obtained by Potentiometric Mass Titration, Croatica Chemica Acta, 2006, 79 (1),

76 [22] C. Jiang-Lin, L. Wen-Hua, Z. Jian-Qing, C. Chu-Nan, Adsorption Behavior and Photooxidation Kinetics of OH- at TiO2 Thin Film Electrodes, Acta Phys. Chim. Sin., 2004, 20(07), [23] J. Poppe, S. G. Hickey and A. Eychmuller, Photoelectrochemical Investigations of Semiconductor Nanoparticles and Their Application to Solar Cells, J. Phys. Chem. C, 2014, 118 (30), [24] G. Garcia Bessegato, T. T. Guaraldo and M. V. Boldrin Zanoni, Chapter 10- Enhancement of Photoelectrocatalysis Efficiency by Using Nanostructured Electrodes, Nanotechnology and Nanomaterials, "Modern Electrochemical Methods in Nano, Surface and Corrosion Science", edited by Mahmood Aliofkhazraei, [25] H. Luth, Chapter 7- Space charge layers at semiconductor interfaces, Solid surfaces, interfaces and thin films,, 6 th edition, Springer, [26] R. N. Pandey, K. S. Chandra Babu, O. N. Srivastava, High conversion efficiency photoelectrochemical solar cells, Progress in Surface Science, 1996, 52(3), [27] J. Li and N. Wu, Semiconductor-based photocatalysts and photoelectrochemical cells for solar fuel generation: a review, Catal. Sci. Technol., 2015, 5, [28] A. J. Nozik, Photoelectrochemical Cells, Phil. Trans. R. Soc. Lond. A, 1980, 295, [29] M. Nan Chong, B. Jin, C. W. K. Chow, C. Saint, Recent developments in photocatalytic water treatment technology: A review, Water Research, 2010, 44, [30] C. Kormann, D. W. Bahnemann, M. R. Hoffmann, Photolysis of chloroform and other organic molecules in aqueous titanium dioxide suspensions, Environ. Sci. Technol., 1991, 25 (3), [31] K. Suttiponparnit, J. Jiang, M. Sahu, S. Suvachittanont, T. Charinpanitkul, P. Biswas, Role of Surface Area, Primary Particle Size and Crystal Phase on Titanium Dioxide Nanoparticle Dispersion Properties, Nanoscale Res Lett, 2011, 6:

77 [32] S. Malato, P. Fernández-Ibáñez, M. I. Maldonado, J. Blanco, W. Gernjak, Decontamination and disinfection of water by solar photocatalysis: recent overview and trends, Catal. Today, 2009, 147, [33] L. Brus, Electronic wave functions in semiconductor clusters: experiment and theory, J. Phys. Chem., 1986, 90(12), [34] V. Diesen, Heterogeneous TiO2 Photocatalysis-Fundamental Chemical Aspects and Effects of Solid Phase Alterations, Doctoral Thesis, KTH Royal Institute of Technology, [35] P. Roy, S. Berger and P. Schmuki, TiO2 Nanotubes: Synthesis and Applications, Angew. Chem. Int. Ed., 2011, 50, [36] I. Sun Cho, Z. Chen, A. J. Forman, D. Rip Kim, P. M. Rao, T. F. Jaramillo, and X. Zheng, Branched TiO2 Nanorods for Photoelectrochemical Hydrogen Production, Nano Lett., 2011, 11, [37] T. Feng, G. Sheng Feng, L. Yan, and J. Hong Pan, Review Article: One- Dimensional Nanostructured TiO2 for Photocatalytic Degradation of Organic Pollutants in Wastewater, Hindawi Publishing Corporation-International Journal of Photoenergy, Volume 2014, Article ID: , 14 pages. [38] R. Govindaraj, M. Senthil Pandian, P. Ramasamy, S. Mukhopadhyay, Synthesis of titanium dioxide nanostructures and their effects on current-voltage (I-V) performance in dye sensitized solar cells, International Journal of ChemTech Research, 2014, 6(13), [39] A. Fujishima, K. Nakata, T. Ochiai, A. Manivannan, and D. A. Tryk, Recent Aspects of Photocatalytic Technologies for Solar Fuels, Self-Cleaning, and Environmental Cleanup, Electrochemical Society Interface, 2013, 22(2), [40] Y. Ma, X. Wang, Y. Jia, X. Chen, H. Han and C. Li, Titanium Dioxide-Based Nanomaterials for Photocatalytic Fuel Generations, Chem. Rev., 2014, 114,. [41] Y. Cui, H. Du and L. Wen, Doped-TiO2 Photocatalysts and Synthesis Methods to Prepare TiO2 Films, J. Mater. Sci. Technol., 2008, 24(5), [42] W. Choi, A. Termin, M. R. Hoffman, The role of metal ion dopants in quantum-sized TiO2: correlation between photoreactivity and charge carrier recombination dynamics, J. Phys. Chem., 1994, 98,

78 [43] A. O. Ibhadon and P. Fitzpatrick, Review-Heterogeneous Photocatalysis: Recent Advances and Applications, Catalysts, 2013, 3, [44] S. Bingham and W. A. Daoud, Recent advances in making nano-sized TiO2 visible-light active through rare-earth metal doping, J. Mater. Chem., 2011, 21, [45] H. Dong, G. Zeng, L. Tang, C. Fan, C. Zhang, X. He, Y. He, Review: An overview on limitations of TiO2-based particles for photocatalytic degradation of organic pollutants and the corresponding countermeasures, Water Research, 2015, 79, [46] D. M. Chen, Z. Y. Jiang, J. Q. Geng, Q. Wang, D. Yang, Carbon and nitrogen co-doped TiO2 with enhanced visible light photocatalytic activity, Ind. Eng. Chem. Res., 2007, 46, [47] R. Asahi, T. Morikawa, T. Ohwaki, K. Aoki, Y. Taga, Visible-light photocatalysis in nitrogen-doped titanium dioxides, Science, 2001, 293, [48] T. L. Thompson, J. T. Yates Jr, TiO2-based Photocatalysis: Surface Defects, Oxygen and Charge Transfer, Topics in Catalysis, 2005, 35(3), [49] A. Zaleska, Doped-TiO2: A Review, Recent Patents on Engineering, 2008, 2, [50] H. Tada M. Fujishima, H. Kobayashi, Photodeposition of metal sulfide quantum dots on titanium(iv) dioxide and the applications to solar energy conversion, Chem Soc Rev, 2011, 40, [51] P. V. Kamat, Quantum Dot Solar Cells. Semiconductor Nanocrystals as Light Harvesters, J. Phys. Chem. C, 2008, 112 (48), [52] M. Pelaez, N. T. Nolan, S. C. Pillai, M. K. Seery, P. Falaras, A. G. Kontos, P. S. M. Dunlop, J. W. J. Hamilton, J. A. Byrne, K. O'Shea, M. H. Entezari, D. D. Dionysiou, A review on the visible light active titanium dioxide photocatalysts for environmental applications, Applied Catalysis B: Environmental, 2012, 125, [53] T. J. Macdonald and T. Nann, Quantum Dot Sensitized Photoelectrodes, Nanomaterials, 2011, 1,

79 [54] S. Ruhle, M. Shalom, and A. Zaban, Quantum-Dot-Sensitized Solar Cells, Chem. Phys. Chem., 2010, 11, [55] A. J. Nozik, M. C. Beard, J. M. Luther, M. Law, R. J. Ellingson, and J. C. Johnson, Semiconductor Quantum Dots and Quantum Dot Arrays and Applications of Multiple Exciton Generation to Third-Generation Photovoltaic Solar Cells, Chem. Rev., 2010, 110, [56] J. Hui Rhee, C.-C. Chung and E. Wei-Guang Diau, A perspective of mesoscopic solar cells based on metal chalcogenide quantum dots and organometal-halide perovskites, NPG Asia Materials, 2013, 5, 68, doi: /am [57] N. Balis, V. Dracopoulos, K. Bourikas, P. Lianos, Quantum dot sensitized solar cells based on an optimized combination of ZnS, CdS and CdSe with CoS and CuS counter electrodes, Electrochimica Acta, 2013, 91, [58] J. Tian, R. Gao, Q. Zhang, S. Zhang, Y. Li, J. Lan, X. Qu, and G. Cao, Enhanced Performance of CdS/CdSe Quantum Dot Co-sensitized Solar Cells via Homogeneous Distribution of Quantum Dots in TiO2 Film, J. Phys. Chem. C, 2012, 116 (35),

80 ά 3 έ έ ά ή 3.1: ή ά ά ί ί ί ή ό έ ή ό ύ ό ώ ά ό

81 ή. Έ...,. 3.1 ή ό ώ ό ί ώ.,.,., (SnO2:F, Fluorine doped Tin Oxide, FTO) (In2O3:Sn, Indium Tin Oxide, ITO). (>80%). Π

82 . FTO. ί 3.1: ά ά ά ώ ά FTO ITO. ά ώ ό έ ό (S/cm) έ έ cm -3 ) ό έ (cm 2 /Vs) ή ό έ ( C) SnO2:F (FTO) ~1x10 3 ~4x10 20 ~30 < 700 C In2O3:Sn (ITO) ~1x10 4 ~10 21 ~40 < 350 C ή ί TiO2 FTO ( : 8 Ω/ ).,. TiO2,..,., TiO2 (sol-gel) Degussa P25. (nc-tio2) :.,,

83 . sol-gel TiO2.,,., sol-gel TiO2 : 3.5 gr Triton X-100 (t-oct-c6h4-(och2ch2)xoh, x= 9-10) 19 ml (CH3CH2OH)., 3.4 ml (CH3COOH) 1.8 ml (Ti[OCH(CH3)2]4) 20 min.. Ω 3 [1].,., (Triton X-100). Triton X ( 3.2). 3 Οι σ ο ι ές α ι άσ ις ό σ ς αι ο ισ ού ο αϊσο ο ο ι ίο ο ι α ίο ί αι οι ής: Υ ρό υση: Ti (OCH(CH3)2)4 + H2O Ti (OCH(CH3)2)3OH + (CH3)2CHOH, Πο υ ρισ ός: Ti (OCH(CH3)2)3OH+Ti (OCH(CH3)2)4 Ti2O(OCH(CH3)2)6+(CH3)2CHOΗ αι σ ο ι ή α ί ασ ς ό ς ι ασίας ί αι: Ti (OCH(CH3)2)4 + 2H2O TiO2 + 4(CH3)2CHOH. Η αφή ο ισο ο ο ι ίο ο ι α ίο ο ό ο ί σ βίαι ό σή ο αι ά σ α αβύθισ ι ή α ος ο ι ίο ο ι α ίο TiOH ο ο οίο σ σ έ ια ο ί αι αι ο ί σ ο σ α ισ ό ά ο έθο ς σ α ι ί TiO 2 α ο οιό ο φ ο ή

84 TiO2. ή 3.2: ή ή ύ Triton X-100. (dip coating) sol-gel TiO2 ( 3.3).,,.,,.,, Π 550 C ( 20 C/min) 10 min nm FE-SEM

85 ή 3.3: ί ό ί έ ί ό ιξυ θτζωξσμ. sol-gel TiO2., Degussa P25 / (3:1). : 0.3 g Degussa P25, 0.5 ml CH3COOH 5 min., 1.5 ml.., CH3CH2OH., 1 ml ml CH3CH2OH 6 ( 17.5 ml ). 50 ml CH3CH2OH. 10 g Terpineol (C10H18O) 2.82 g CH3CH2OH (10% w/v ). 35 C

86 TiO2 doctor blading ( 3.4) 550 C ( 20 C/min) 10 min. 3.4 m - 2. ή 3.4: ή ά ύ ί έ doctor blading [2] ί ί TiO2. CdS, PbS ZnS, ω (Successive Ionic Layer Absorption and Reaction, SILAR method).,,. TiO2.,

87 3.5. Silar. ή 3.5: ή ά ό ώ ώ έ ή ό ί ό SILAR method) [3]. CdS/TiO2: CdS 3 Cd 2+ : Cd(NO3)2 4H2O (98%), 3CdSO4 8H2O ( 98%) Cd(CH3COO)2 2H2O (98%). S 2- Na2S 9H2O ( 98%)., 0.1. TiO2 5 min.,., 5 min. Silar

88 CdS 10. ZnS/TiO2: ZnS Silar : 0.1 Zn(NO3)2 6H2O 0.1 Na2S 9H2O. 2 Silar. CdS-ZnS/TiO2: CdS-ZnS 0.1 Cd(NO3)2 4H2O Zn(NO3)2 6H2O. S 2- Na2S 9H2O., 10 Silar. PbS/TiO2: PbS TiO2 CdS ZnS., 0.1 Pb(CH3CO )2 3H2O 0.1 Na2S 9H2O. TiO2 2 Silar. CdSe, ZnSe Sb2S3 (Chemical Bath deposition, CBD). CBD,. TiO2. TiO2 [4,5]. CdSe/TiO2:, 0.08 Se 0.02 Na2SO3 (

89 , Reflux) 80 C 15 h., 0.08 CdSO4 8/3H2O 0.12 N(CH2COONa)3 H2O.,., (5 C) 4 ½ h. ZnSe/TiO2: ZnSe CdSe 0.08 CdSO4 8/3H2O 0.08 Zn(NO3)2 6H2O. CdSe-ZnSe/TiO2: CdSe-ZnSe, CdSe CdSO4 8/3H2O Zn(NO3)2 6H2O. Sb2S3/TiO2: 2 ml Sb2S3 ( 1 ) 20 ml Na2S2O3 ( 1 ).,, 5 C 80 ml., TiO2 10 C 2.. QDs. : CdS-ZnS/TiO2, CdSe/CdS/TiO2, ZnS/CdSe/CdS/TiO2, CdSe-ZnSe/TiO2, CdS/PbS/TiO ή ί WO3 TiO2 WO

90 WO3 FTO., sol-gel WO3 : 0.4 g W (10 m, 99.99%) 3 ml H2O2 (30 wt% H2O)., H2O2 Pt ( 12 h)., 3 ml CH3CH2OH 0.3 g Triton X-100., FTO doctor blading 500 C (20 C/min) 10 min. - 5 WO mg/cm ή ί ΑξΦO4 Έ BiVO4 FTO.,. sol-gel BiVO4 : : 0.12 Bi(NO3)2 5H2O CH3COOH 0.12 V(C5H7O2)3 CH3COCH2COCH3., 1 ml Triton X g/ml. FTO doctor blading 500 C (20 C/min) 10 min nm

91 . ή ό ώ 4,.. Ω,,.,. Έ, ( ) : (1) NiO, (2) NiO (3) (graphene-based sulfur-doped porous carbon nanosheets). WO3, Pt FTO.,, : (1) CuS, CoS FTO (2) Cu2S. 4 Ως έ ο ό ο ο ί αι ο ά ισ ο έ ο ο α αι ί αι ια α ι ήσ ι έ α ό ιο ις ι ές ά ις ο ι ού σ α ό α ό α ό οι α φο ία έσα σ έ α έ α ο αι α α ο α θ ί ύθ ο α ό ο α ι ό έ α

92 .. ό ί Pt ύ ά,. Έ (Carbon Cloth, CC)... :, 2.46 g (Vulcan XC 72) 60 ml 0.8 ml PTFE (polytetrafluoroethylene, 60 wt% H2O) ( C:PTFE=70:30) mixer (2500./min)., carbon cloth 80 C 30 min. Έ, 340 C 30 min PTFE., g Pt C (30% Pt on Vulcan XC 72), 0.52 ml (Nafion, 5 wt. % ), ml 0.45 ml. 80 C. 0.5 mg Pt/cm 2 ( )

93 3.2.2 ή ή ά ύ ώ,,.,. (Multiwalled carbon nanotubes, MWCNTs)., 0.35 nm nm cm. ( ).,. MWCNTs : 7 g ml CH2Cl g. 20 h, PTFE ( : 0.2 m) CH2Cl ml CH2Cl C. films PTFE 230 m 7 cm [6].. NiO Carbon Cloth., 1 g NiCl2 1 g Triton X-100., 3 ml 6 ml., 400 C 30 min

94 3.2.3 ύ ύ ά έ έ έ ί,. Jiao Tong ( ). 3.6 :, (Reduced graphene oxide, RGO) p-. RGO, (DMF, 1.0 mg/ml),., 1,3,5-2,5- RGBr, DMF Hagihara-Sonogashira., GMP-S, 700, όc 2 h (GMC-S700, GMC-S800 GMC- S900). : 10 mg (GMC-S700, GMC-S800 GMC-S900) 1.3 ml 0.5 ml., 0.1 ml (PTFE, 60 wt% H2O). CC 340 όc 20 min. 10 cm 2 (3.0cm 3.3cm) 5 mg [7]

95 ή 3.6: ή ί ύ GMP-S GMC-S. (i) Sodium dodecylbenzenesulfonate, N2H4 H2O, 100 C, 8 h, (ii) 4-bromobenzenediazonium tetrafluoroborate, 0 C έ ί ί, 2 h, (iii) Ar, Pd[(PPh3)4], CuI, Et3N, DMF, 80 Β, 3 days (M1: 1,3,5-triethynylbenzene; M2: 2,5- dibromothiophene), (iv) Ar, ί ί έ 700, 800 and 900 Β, 5 Β/min, 2 h. Ω GO RGO ί ί ί έ ί ί ί [7] ό ί Pt ί FTO WO3 BiVO4, Pt FTO.,, (Elcocarb C/SP (Solaronix)) FTO doctor blading

96 450 C 30 min., Pt Diamminedinitritoplatinum(II) (3.4 wt.% NH4OH) CH3CH2OH ( 99.8%) 450 C 15 min. Pt 0.1 mg/cm ό ύ ά ί FTO,., [8]., (CuS, CoS) FTO Cu2S. CuS/FTO: FTO,. CuS FTO. 0.5 mol/l Cu(NO3)2 H2O CH3OH 1.0 mol/l Na2S 9H2O - (50% v/v)., Cu(NO3)2 H2O.,.,. 15. CoS/FTO:,. CoS FTO., 5 mmol/l CoCl2 6H mol/l NH2CSNH2 (Thiourea). Έ,

97 ph 6., FTO, - Ag/AgCl. 1 cm.,, 1.2 V +0.2 V 5 mv/s., FTO CoS, 100 όc 20 min. Cu2S/ :., HCl (37%) 70 όc 5 min., 1.0 mol/l Na2S 9H2O όc 1.0 mol/l S. 5-7 min 100 όc 10 min.. ύ ί ί,,.,,.,. ph.,, NaOH

98 ., Na2SO4, LiClO4, NaClO4 NaCl., Na2S, Na2SO3 ( S/Na2S). Ό ( ). : Na2S 9H2O 1M C. Έ, S (99.998%) Na2S ά ή ή ώ ή.,, ή ή ί., Φ

99 ., ( Xe, Oriel 450W) 100 mw/cm 2. Xe 3.7. ή 3.7: ή ή ά Xe ύ ό [9] ή ώ ή Έ.., 5.5 x 6.0 x 5.5 cm Plexiglas ( 3.8)

100 ή. : ή ά ή ή ά ή ώ ή ύ ύ ί cm. 0.5 cm.,.,.,,., SiO2-88 -

101 . Π mm 2 mm. ί 3.2: ή ύ ώ ί VitraPOR (Robu, Germany) ή ά ή ί ύ ά. Silica, SiO % Magnesium oxide, MgO 0.05% Boric oxide, B2O % Iron oxide, Fe2O3 0.04% Sodium oxide, Na2O 4.20% Calcium oxide, CaO 0.10% Alumina, Al2O3 2.20% Chlorine, Cl 0.10%,, Plexiglas, 5.0 x 4.5 x 3.5 cm 1.5 x 1.5 cm., 1 cm. Ό, Pyrex Glass. 55 mm 10 cm ( 3.9).. Ό, 5. 5 Για ιο ία ι ής ό σ ς chemical bias) α ύ α ό ο αι αθό ο ο ού α σι ο οι θού ο ύ ς ιαφο ι ές ι ές ph. Σ α ή ί σ σ ο ια έ ισ α ς α ό ο ο οθ ί αι ά οιος βασι ός ο ύ ς.. NaOH) ώ σ άθο ο ό ι ο ιά α (.. H 2 SO 4 )

102 ή. : ή ά ή ύ ά ή ά ή ί ό ά ώ ή, ( 3.10). - (linear sweep voltammetry), AUTOLAB PGSTAT 128N NOVA

103 ή 3.10: ή ά ή ώ ή ή ί ά Ό,.., (Reference electrode)., ( ). Π

104 ί 3.3: ά ά ί ά ή. ό ά ά ή ό vs SHE) RHE (Reversible Hydrogen electrode) SHE (Standard Hydrogen electrode) ό ύ ύ ύ έ έ H2) [H + ] = 1.18 mol/l p(h2) =10 5 Pa E0= 0.00 E0= x ph 0.1 M KCl Ag/AgCl 3 M KCl έ KCl ή. : ή ά ί ί ύ ή ό ώ ί ά ό ό ί ό ά

105 3.5 ί ώ ή ή ή ή ί,, ( ). -,. 5 mv/s. ( )..,,, [10]., έ ό ή ί ύ IPCE).,

106 ί ή έ (Electrochemical Impendance Spectroscopy),.. /,., ( ). ( ),, ( ). : = +. j (j j = -1).,.., Nyquist. Nyquist, =, Nyquist

107 ή 3.14: ά Νyφuξψω ύ ό ύ ά ί R) έ ή C) έ ά. Έ - Randles. (Rs) / ( 3.15). ή 3.15: ύ ό ύ Randles (Ref. el.: ό ά, WE: ό ί, CE: ό. Rs,. Rp

108 , - (Rct).,, Cdl. 3.6 Μ ή ή ί ό, ( Xe, Oriel 450W) 100 mw/cm 2. SRI 8610C, ( Silica Gel). (Molecular sieve) silica gel H2, O2, N2, CH4 CO., 0.25% 2 Ar. :,. Ω Ar Φ (21 cc/min). 10-, 600 C. Silica Gel Molecular Sieve.,, (Thermal Conductivity Detector, TCD)., ( 3.17)

109 ή 3.17: έ ό ά ή ή ό. PeakSimple Έ ή 3.18: ή ό ή έ ί

110 3.7 έ ύ ά 3.7. ή ί ά SEM) (Scanning Electron Microscopy, SEM)..,.,. (x y).,,, (secondary), (backscattered) -. SEM, ( ) Zeiss SUPRA 35VP 1.5 nm 20 V 2nm 30 V. Π (EDX) (QUANTA 200, Bruker AXS) ή ί ό (Transmission electron Microscopy, TEM). Ό,

111 ,., ( ),.,. EM, Έ ί ά ά ύ- ώ - (Diffuse Reflectance UV-Vis Spectroscopy).,. Ό 3.19,. ή 3.19: ή ά ή ά ά ό ό ώ

112 DRS,.. (.. BaSO4)., ή 3.20: ή ό ά ό έ ά ά ί ή [10]. Ω nm.., nm,. Ω FTO. ( ) - (UV-VIS Spectrophotometer, Shimadzu MODEL 2600)

113 3.7.4 ί ί (X-ray diffraction, XRD) Π, Å,., ΠX. Π.,, ΠX, ΠX (diffraction pattern).., (l) XRD Scherrer: =. Ό : : 0.9, : Π, :, :. Π ( ) D8 ADVANCE (Bruker AXS Gmbh)

114 3.7.5 ί ί ί ί ί ό ώ ί Π (X-ray Photoelectron Spectroscopy (XPS)). Π. Ό Π.. XPS 1-10 nm., : =., : h : Π : : XPS Π,. (Ultraviolet Photoelectron Spectroscopy (UPS)) XPS. -., µ. UPS UV

115 (ionization cross-section),,. Π ( ) SPECS LHS-10. UPS HeI h = ev (model UVS 10/35) Constant Retarding Ratio (CRR) mode CRR = 10. o V, UPS

116 ί [1].,,,, [2] A. Berni, M. Mennig, H. Schmidt, Sol-Gel Technologies for Glass Producers and Users, Chapter Doctor Blade, pp 89-92, M.A. Aegerter et al. (eds.), Springer Science+Business Media, New York, [3] N. Asim, S. Ahmadi, M. A. Alghoul, F. Y. Hammadi, K. Saeedfar and K. Sopian, Review Article: Research and Development Aspects on Chemical Preparation Techniques of Photoanodes for Dye Sensitized Solar Cells, International Journal of Photoenergy, 2014, Article ID: , 21 pages, [4] C. D. Lokhande, Review: Chemical deposition of metal chalcogenide thin films, Mater. Chem. Phys., 1991, 27, [5] P. K. Nair, M.T.S. Nair, V. Μ. Ζζχθı ζ, O. L. Arenas, Y. Peña, A. Castillo, I.T. Ayala, O. Gomezdaza, A. Sánchez, J. Campos, H. Hu, R. Suárez, M. E. Rincón, Semiconductor thin films by chemical bath deposition for solar energy related applications, Solar Energy Materials and Solar Cells, 1998, 52 (3 4), [6]. ά, ί ό ύ ώ ή ή, ή ή, ή ώ,. [7] S. Sfaelou, X. Zhuang, X. Feng and P. Lianos, Sulfur-doped porous carbon nanosheets as high performance electrocatalysts for PhotoFuelCells, RSC Adv., 2015, 5, [8] G. Hodes, J. Manassen and D. Cahen, Electrocatalytic Electrodes for the Polysulfide Redox System, J. Electrochem. Soc., 1980, 127 (3), [9]. ά, έ ή ή ό ή έ έ ό / έ ά, ή ή, ή ώ,. [ ]. ί, ί ή ή, ό ί ί,

117 [11] B. M. Weckhuysen, R. A. Schoonheydt, Recent progress in diffuse reflectance spectroscopy of supported metal oxide catalysts, Catalysis Today, 1999, 49,

118 έ

119 ά 4 ί ί ή ή έ ά ώ ό ώ

120 ή Ό,.., TiO2.,.,,.. X ό ώ ό ό ί TiO2 TiO2. Ό,., TiO2 (sol-gel) Degussa P-25. sol-gel TiO2 4.1., 6.5 nm TiO nm

121 ή 4.1: ό SEM ό ί TiO2 έ ί ό ά ύ ή sol-gel) ή ά TiO2 ό ή Degussa P-25. TiO2 sol-gel TiO2 (TiO2(s-g)) TiO2 (TiO2(P-25)). 4.2 ( ). ( 1) ( 2) FTO 320 nm. TiO2(s-g) ( 3) 300 nm., ( 4) TiO2, 7.5 m.,

122 ή 4.2: ί SEM ί TiO2 ά ό έ ώ ί FTO. ώ ί ί ή : ί, ώ ί FTO, (3) ί ί ό ά sol-gel (TiO2(sg)), (4) ί ί ό ό ά ή ή Degussa P-25 (TiO2(P-25)). TiO nm SEM

123 ή 4.3: ό EM ί TiO2 έ ί ό ά ύ ή sol-gel) ή ά TiO2 ό ή Degussa P ό ό ύ ό Ό, TiO2 Silar,. CdS, Silar 3 Cd 2+., Cd(NO3)2, CdSO4 Cd(CH3COO)2. Ό CdS Cd(NO3)2 ((CdSN)), SEM ( 4.4) TiO2 CdSN/TiO2., CdS

124 ή 4.4: ί SEM ί TiO2 ά έ ώ ί FTO ί TiO2 έ CdSN. (CdS/TiO2), Π SEM. 4.5 TEM HR-TEM. : 4.9±1.2 nm CdSN, 5.7±1.1 nm CdS CdSO4 (CdSS) 7.1±1.5 nm CdS Cd(CH3COO)2 (CdS ). 25. CdS [1]., EDX Π 4.1. CdSN (1.8%) CdS (7.4%). S, Cd Cd

125 ή 4.5: ό HR-TEM: (a) ί TiO2 ί TiO2 έ CdS Cd 2+ : (b) Cd(NO3)2, (c) CdSO4 ι Βι θ 2. ί 4.1: ό ό ί ύ έ EDX ά ί CdS/TiO2. ό ό % ό έ Cd 2+ O * Ti Cd S Cd(NO3) CdSO Cd(CH3COO) * ό ά ό ά ό ό /Ti ά ί ό ί

126 S 2- Silar.,,. Έ CdS CdS ph [2]. (pzc), 6.0±0.2 [3].., ph Cd(NO3)2 5.7 Cd(CH3COO)2 6.9 CdSO4 4.0.,, ph. Cd 2+,. Φ. Έ ZnS/CdSe/CdS /TiO2., SEM ( 4.6), TiO2. Ό CdS, 5 nm

127 ή 4.6: ό SEM ά : A) ί TiO2 (B) ί TiO2 έ CdSN, CdSe ZnS (ZnS/CdSe/CdS /TiO2) έ ί TiO2 ί ί Π. 4.7 XRD FTO sol-gel Degussa P-25. TiO2 550 C,. TiO2(s-g) TiO2(P-25) 70/30 Degussa P-25. FTO., Scherrer TiO2 TiO2(s-g) 10 nm TiO2(P-25) 28 nm

128 ή 4.7: ά XRD ί ί ί έ ί ά ό FTO ό ή sol-gel ά ή ά ό Degussa P-25 ά

129 4.1.4 έ ό ί ά ά ύ- ώ UV-Vis DRS) -. DRS TiO2. Ό CdS/TiO2, CdS, Cd 2+ Silar. [4,5]. - TiO2 CdS 4.8.,, TiO2 CdS. Ό CdS Cd 2+, CdS TiO2. Ά, CdS. DRS., CdSN CdS. CdSS, CdSN CdS

130 ή 4.8: ά ά ά ύ- ώ έ TiO2 έ TiO2 έ CdS Cd 2+ : Cd(NO3)2, CdSO4 Βι θ 2. DRS TiO2 CdSN ZnS, Silar. Ό 4.9, TiO2 ZnS/TiO2,. ZnS CdSN,., CdSN/TiO2,.,. TiO

131 ( G), ( g) : ev = nm. Έ, CdS /TiO ev CdS -ZnS, ZnS., ZnS (25%)-CdS (75%) 2.58 ev, - (ZnS (50%)-CdS (50%)) 2.64 ev ZnS (75%)-CdS (25%) 2.67 ev. ή 4.9: ά ά ά ί TiO2 ό ώ ά CdS -ZnS. ύ ύ ά ά Cd Zn ό ύ ά ή ά έ Silar: (1) TiO2, (2) ZnS (100%)/TiO2, (3) ZnS (75%)-CdS (25%)/TiO2, (4) ZnS (50%)-CdS (50%)/TiO2, (5) ZnS (25%)-CdS (75%)/TiO2, (6) CdS (100%)/TiO2 [6]

132 ,, CdS. CdSe, ZnSe CdS /TiO F (R) Wavelength (nm) ή 4.10: ά ά ά ί CdSN/TiO2 ό ώ ώ ά CdSe-ZnSe: (1) CdSN/TiO2, (2) 100% ZnSe/ CdSN/TiO2, (3) 50% ZnSe-50% CdSe/CdSN/TiO2, (4) 30% ZnSe-70% CdSe /CdSN/TiO2 (5) 100% CdSe/CdSN/TiO

133 ZnSe Eg=2.7 ev, CdS (Eg=2.5 ev )., CdSe, 610 nm. CdSe ZnSe CdS /TiO2, ZnSe, [7]. PbS Sb2S3. TiO2 PbS, ( 4.11), 800 nm PbS. ή 4.11: ά ά ά ί TiO2 έ ά ί ώ ώ (PbS, PbS/CdS, CdS, CdSe ZnSe)

134 TiO2 Sb2S3. Sb2S3 (Eg=1.7 ev ), nm. ή 4.12: ά ά ά ί TiO2 ί TiO2 έ Sb2S ή έ ί CdS/TiO2 UPS TiO2 CdS Cd 2+, UPS. TiO2 CdS/TiO (IP) (

135 ). 2,. ( Fermi) Fermi. ( ),... Π 4.2. TiO2 7.4 ev CdSN CdSS (6.6 ev 6.7 ev)., CdS (5.7 ev). ή 4.13: ά UPS ί : (a) TiO2 ί TiO2 έ CdS ή ώ ό ώ : (b) CdSN/TiO2, (c) CdSS/TiO2, (d) CdSA/TiO

136 ί 4.2: έ ύ ύ I.P. ί έ TiO2 ή ί έ CdS. ά I.P. (ev) TiO2 7.4 CdSN/TiO2 (Cd(NO3)2) 6.7 CdSS/TiO2 (CdSO4) 6.6 CdSA/TiO2 (Cd(CH3COO2)) ό ώ ό ό ώ (Carbon Cloth, CC).,. SEM Ό, 10 m.,,. Έ (Multi-walled carbon nanotubes, MWCNTs). NiO. SEM ( 4.15) MWCNTs,.,

137 . NiO. NiO 70 nm. SEM NiO CC. ή 4.14: ό SEM ό : A) Carbon Cloth (CC), (B) ί Pt έ CC CC ά ό ό ό ά ά Pt

138 ή 4.15: ό SEM ό : A) MWCNTs (B) NiO έ MWCNTs., (GMC-S-X). SEM nm m.,. SEM,

139 ή 4.16: ό a) SEM ό b ύ ά έ έ έ ί έ ή ά ώ ΖΜΒ-S-X GMC-S-X (X=700, C) -., : 462 m 2 g -1 GMC-S-700, 530 m 2 g -1 GMC-S m 2 g -1 GMC-S-900. X=700, Π

140 ί 4.3: έ ό ύ ά έ έ έ ί. ί ή ά (SBET) /m 2 g -1 Ό ό (Vmicro) /cm 3 g -1 ή ά ό (Smicro) /m 2 g -1 ό ό ό (VTot) /cm 3 g -1 Μέ ά ό (Dav) /nm GMC-S GMC-S GMC-S ή έ XPS GMC-S-X GMC-S-X XPS., 3 ( 4.17 ). S GMC-S700, GMC-S800 GMC- S %, 5.02% 4.74% ev ( 4.17 ) ev CΠSnΠC ( n= 1 2) ev ΠC=SΠ ev (Π SOnΠ)

141 ή 4.17: ά XPS GMC-S700, GMC-S800 GMC-S

142 4.3 ά ά ό ί ί έ ί ί ύ ή ό ή ύ ά,. glass frit.,.,, [8] TiO2 Pt/CC..,, JSC 1.0 ma/cm 2 VOC 1.2 V ( 1) 1.8 ma/cm V ( 2). glass frit.,, [7,9]

143 ή 4.18: ά ύ - ά ί ί ύ ά ό ά ή ά: ά : nc-tio2/fto, ό : Pt/CC, ύ : a. (+5% EtOH). ί EtOH ί ό έ ό ί ί ό έ Ό,.,. - TiO ,

144 , (JSC: 0.61 ma/cm 2, VOC: 1.03 V EtOH JSC: 0.14 ma/cm 2, VOC: 0.84 V EtOH). ή 4.19: ά ύ - ά ί ί ό ά ί ί ό ή ά: ά : nc-tio2/fto, ό : Pt/CC, ύ : a. (+5% EtOH). D ί ή ό L ή ό ό

145 ,.,.,. Έ / (Current doubling/multiplication effect) ( ) TiO2 - [10-12].,, - [13]. Ό (VOC),., TiO2,..,. ( ), - ( Ag/AgCl) ( 4.20). Π 4.4. Ό, 10% v/v.,

146 ή 4.20: ά ύ - ά ί ί ύ ί ή ί ά μ/ gcl) ό ή ό : Ά : nc-tio2/fto, ό : Pt/CC, ύ :. Na ά ά έ ό : % v/v, (2) 0.1% v/v, (3) 0.5% v/v, (4) 2.0% v/v, (5) 5% v/v, (6) 10% v/v, (7) 20% v/v

147 ί 4.4: ί έ έ ό έ ύ ύ ά ύ ώ ί ί. ό έ ό % v/v) JSC (ma/cm 2 ) VOC (Volts) ί ί ύ ύ,.. Na2SO4, NaOH. Έ [14]., TiO2, (NaOH, LiOH, KOH, NH4OH), 3 ( Ag/AgCl) TiO2 Pt., ( - ) (Na +, Li +, K +, NH4 + )

148 ή 4.21: ά ύ - ά ύ ί ή ί ά μ/ μβρ ό ή ό : Ά : nc-tio2/fto, ό : ύ Pt, ύ :. ό ί : (1) Li +, (2) Na +, (3) K + (4) NH4 +. ί έ ί έ ά ό Angstroms V vs Ag/AgCl,. Ό,. Ό,.,

149 TiO2., Li +, NH4 +. LiOH ( 4.22).. ή 4.22: ά ή ί ό ή ό ύ ώ ί ή ί ά Ag/AgCl: Ά : nc-tio2/fto, ό : ύ Pt, ύ :. Li

150 ,, -. LiOH 4.23., TiO2, ( 4.23a). Ό TiO2 ( 4.23b),,,. Έ, ph. (NaCl, NaClO4, Na2SO4, CH3COONa NaOH) ( 4.24). ph Π 4.5. ph,. NaOH

151 ή 4.23: ά ύ - ά ό ή ό ύ ώ ί ώ ά nc-tio2/fto ό ύ Pt: (a) ά ώ LiOH ή ύ : (1) 0.05 M, (2) 0.2 M 0.5 M (b) ά ά ί TiO2: (1) 0.35 m, (2) 1.5 m, (3) 5 m (4) 10 m

152 ί 4.5: ύ ά ί ή ύ έ ί ph ό ό ό TiO2 ί έ ph. Η (C= 0.2 M) ph NaCl 6.1 NaClO4 6.2 Na2SO4 7.1 CH3COONa 8.5 NaOH 13.2 ή 4.24: ά ύ - ά ό ή ό ύ ώ ί ώ ά nc-tio2/fto, ό ύ Pt ά ά ύ Na + ύ : NaCl, (2) NaClO4, (3) Na2SO4, (4) CH3COONa (5) NaOH. έ ύ ά ί ή

153 , TiO2. LiOH (0, 0.1, v.% EtOH). 4.25a -., 5% v/v EtOH.,. ( 4.25b),,, [15]

154 ή 4.25: ά ύ - ά ί ί a) ό ή ό (b) ό ό ύ ώ ί nc-tio2/fto ά, ύ Pt ό,. LiOH ύ ά ά ό : v/v%, (2) 0.1 v/v%, (3) 1 v/v% v/v%

155 4.4 ί TiO2 έ ί.,. TiO2 [16]. Έ CdS. TiO2, CdS [17,18]. Ό, CdS Silar Cd 2+ (Cd(NO3)2, CdSO4 Cd(CH3COO)2) Silar, [19,20]. CdS/TiO2, CdS, Cd 2+. CdS CdS TiO2,. - ( 4.26), CdSA/TiO2,, CdS /TiO

156 A B ή 4.26: A. ά ύ - ά ί ί ή ά: ά : nc-tio2, (2) CdSA/ nc-tio2, (3) CdSS/ nc-tio2, (4) CdSN/ nc-tio2, ό : Pt/CC, ύ : 0.5 M NaOH + 5% v/v EtOH. B. ά ά ά ί TiO2 ί TiO2 έ CdS ώ ά ό ά Cd 2+ (N: nitrate, S: sulfate, A: acetate)

157 , TiO2 CdS,. UPS. Ό, CdS,.., V vs SHE., CdS., HO V vs SHE ( ph=14). CdSN/TiO2 HO CdS /TiO2. CdSS, CdS. VOC,., Π 4.6., CdSN/TiO2., CdSN/TiO2, IPCE IPCE ( 4.28)

158 ή 4.27: έ ώ έ ί nc-tio2 FTO ί CdS/nc-TiO2/FTO έ έ ή ώ ό ά Cd 2+ έ ά ή ύ ό ό ά. ά ά ώ ώ CdS ά ί ή έ ί ό ά DRS. ό VB ή έ IP ί 4.2 ώ. ev ή SHE V ph=14 (-0.059x14). ί 4.6: έ ύ ύ, ά ύ ώ ά ή ό έ TiO2 ή ί ή CdS. JSC (ma/cm 2 ) VOC (Volts) F.F. ό % TiO ό ά Cd 2+ Cd(NO3) CdSO Cd(CH3COO)

159 ή 4.28: ύ ά ά ά CdSN/TiO2 ό ή ί ύ IPCE) έ ά, Pt/CC ό ύ. NaOH+5% EtOH., CdS/TiO2, ( 4.29). CdS /TiO

160 ή 4.29: ή ό ύ ά ό ό ί ί ή ά: ά : nc-tio2 έ CdS ώ ά ό ά ί : Cd(NO3)2, (2) Cd(SO4)2, (3) Cd(CH3COO)2 ( ό ή: cm 2 ), ό : Pt/CC, ύ :. NaOH + 5% v/v EtOH. CdS/TiO2 CdS-ZnS [21,22]. CdS, CdS ZnS/TiO2 UV

161 ή 4.30: ά ύ - ά ί ί ή ά: ά : έ TiO2 έ ί CdS -ZnS έ ί : (1) ZnS(100%)/TiO2, (2) ZnS(90%)-CdS (10%)/TiO2, (3) ZnS(75%)-CdS (25%)/TiO2, (4) ZnS(50%)-CdS (50%)/TiO2, (5) ZnS(25%)-CdS (75%)/TiO2, (6) CdS (100%)/TiO2, ό : Pt/CC, ύ : 0.5 M NaOH + 5% v/v EtOH., CdS (10%)., CdS ZnS (25%) CdS/TiO2. Ό, ZnS/TiO2. VOC, TiO

162 . Ω,. Έ 30 min ή. : έ ό ύ ύ ή ύ Cd ό ά ύ ZnS(25%)-CdS (75%)/TiO2 ί ί ή ά: ά : ZnS(25%)-CdS (75%)/TiO2, ό : Pt/CC, ύ : 0.5 NaOH + 5% v/v EtOH. ά ύ ί έ ύ ύ έ ά ό min) ώ ά ύ ά ό min ό ό

163 Cd 30-70%. JSC ZnS(25%)-CdS (75%)/TiO2. Έ 30 min, % CdS-25% ZnS 100% CdS. CdS, TiO2. ή 4.32: ά ύ - ά ί ί ή ά: ά : ZnS(25%)-CdS (75%)/TiO2, CdS (100%)/TiO2, ό : Pt/CC, ύ : 0.5 NaOH + 5% v/v EtOH

164 Έ CdSe, Sb2S3 PbS CdS ZnS., DRS,.,.,. Ό 4.33,,. Ό ( 4.33 ), Fermi., ZnS/CdSe/CdS /TiO2 PbS Sb2S , CdS ZnS,. ή 4.33: ά ί ά ά : έ ύ ύ έ έ ή

165 ή 4.34: ά ύ - ά ί ί ώ ά nc-tio2 έ ά ί ώ ώ : (1) PbS/TiO2, (2) Sb2S3/TiO2, (3) Sb2S3/75%CdS- 25%ZnS/TiO2, (4) CdSe/75%CdS-25%ZnS/TiO2 (5) 75%CdS-25%ZnS/ io2, ό Pt/CC ύ 0.5 NaOH + 5% EtOH., ZnSe CdS CdSe ZnSe CdSe., CdS,

166 ή. : ά ύ - ά ί ί ώ ά nc-tio2 έ ά ί ώ ώ : (1) CdS /TiO2, (2) ZnSe/CdS /TiO2, (3) ZnSe(50%)-CdSe(50%)/CdS /TiO2, (4) CdSe/CdS /TiO2. A ό : Pt/CC ύ : 0.5 NaOH + 5% EtOH

167 4.5 Μ έ ώ ώ, Pt. Έ (MWCNTs). NiO Pt/CC NiO/CC. Ό ZnS(25%)-CdS(75%)/TiO Π 4.7 JSC VOC. Ό, CC. CC NiO., CC NiO. Pt/CC. NiO/MWCNTs [23]

168 ή 4.36: ά ύ - ά ί ί ά : ZnS(25%)-CdS(75%)/TiO2, : (1) CC, (2) NiO/CC, (3) MWCNTs, (4) NiO/MWCNTs (5) Pt/CC, ύ :. NaOH + 5% v/v EtOH. ί 4.7: έ ύ ύ, ά ύ ώ ό έ έ ύ, ά ή ό ί ί ά ZnS(25%)- CdS(75%)/TiO2 ά ί ί. ό JSC (ma/cm 2 ) VOC (Volts) Μέ ύ (mw/cm 2 ) F.F. n (%) CC NiO/CC MWCNTs NiO/MWCNTs Pt/CC

169 (CC, Pt/CC, MWCNTs),,, Ag/AgCl ( 4.37)., MWCNTs CC Pt/CC.. ή 4.37: ά ή ί ώ ό ί CC, Pt/CC MWCNTs, έ ύ ό ό έ ό Ag/AgCl ό ά. ύ ή. aoh ύ ά ή mv/s ό ώ

170 Έ (GMC-S-X). Pt/CC, 4.38., V.,., onset V 0 V. onset Pt/CC. Pt/CC GMC-S-X. GMC- S-X, GMC-S700. GMC-S700, TiO2 CdS /TiO2., Pt/CC : ( ) TiO2 NaOH ( EtOH), ( ) TiO2 NaOH EtOH (C) CdS /TiO2 NaOH EtOH., GMC-S700 Pt/CC. Ό,. Ω,, onset

171 ή 4.38: ά ή ί TiO2 ά ά ί ί : (1) Pt/CC, (2) GMC-S800, (3) GMC-S900 GMC-S700 ύ ώ o ί ή ί ό ό ά. ύ : 0.5 M NaOH. ή ί ύ ό ύ ά ώ ή ί έ ή ύ ά

172 , onset.,. ή 4.39: ά ή ί ώ ώ ό Οω/ΒΒ ΖΜΒ-S7 /ΒΒ έ ώ : ά : TiO2, ύ :. NaOH ί EtOH, ά : TiO2, ύ :. NaOH + 5% v/v EtOH C ά : CdS /TiO2, ύ :. NaOH + 5% v/v EtOH

173 , 2. Π Pt/CC, 1 ma CdS 25 ma. GMC-S700/CC, Pt/CC 0.3 V., GMC-S700/CC Pt/CC [24]. ί 4.8: έ ύ ύ ά ύ ώ ύ ώ ή ά ή Pt/CC GMC-S700/CC Isc (ma) Voc (Volts) Isc (ma) Voc (Volts)

174 ή 4.40: ά ύ - ά ί ί ώ ό Pt/CC GMC-S700/CC ή ά: ά : TiO2, ύ :. NaOH ί EtOH, ά : TiO2, ύ :. NaOH + 5% v/v EtOH ά : CdS/TiO2, ύ :. NaOH + 5% v/v EtOH. ό ή ό ί ή ό ώ 10 cm 2 (3 cm x 3.3 cm)

175 ί [1] S. Sfaelou, L. Sygellou, V. Dracopoulos, A. Travlos, P. Lianos, Effect of the Nature of Cadmium Salts on the Effectiveness of CdS SILAR Deposition and Its Consequences on the Performance of Sensitized Solar Cells, Journal of Physical Chemistry C, 2014, 118, [2] C. Minero, Surface-Modified Photocatalysts, Chapter in Environmental Photochemistry Part III, Volume 35 of the series The Handbook of Environmental Chemistry, 2013, [3] T. Preocanin and N. Kallay, Point of Zero Charge and Surface Charge Density of TiO2 in Aqueous Electrolyte Solution as Obtained by Potentiometric Mass Titration, Croatica Chemica Acta, 2006, 79(1), [4] Y. Liu, Z. Li, L. Yu, S. Sun, Effect of the nature of cationic precursors for SILAR deposition on the performance of CdS and PbS/CdS quantum dot-sensitized solar cells, Journal of Nanoparticle Research, 2015, 17:132, Doi: /s [5] R. Zhou, Q. Zhang, J. Tian, D. Myers, M. Yin and G. Cao, Influence of Cationic Precursors on CdS Quantum-Dot-Sensitized Solar Cell Prepared by Successive Ionic Layer Adsorption and Reaction, J. Phys. Chem. C, 2013, 117 (51), [6] S. Sfaelou, M. Antoniadou, V. Dracopoulos, K. Bourikas, D. I. Kondarides, P. Lianos, Quantum dot sensitized titania as visible-light photocatalyst for solar operation of photoactivated fuel cells, Journal of Advanced Oxidation Technologies, 2014, 17(1), [7] M. Antoniadou, S. Sfaelou, P. Lianos, Quantum dot sensitized titania for photo-fuel-cell and for water splitting operation in the presence of sacrificial agents, Chemical Engineering Journal, 2014, 254, [8]. Ren and Y. X. Gan, Advances in Photoelectrochemical Fuel Cell Research, Chapter in "Small-Scale Energy Harvesting", book edited by Mickael Lallart, ISBN , [9] Y. Wang, S. Zou and W.-B. Cai, Review: Recent Advances on Electro- Oxidation of Ethanol on Pt- and Pd-Based Catalysts: From Reaction Mechanisms to Catalytic Materials, Catalysts, 2015, 5,

176 [10] P. Lianos, Production of Electricity and Hydrogen by Photocatalytic Degradation of Organic Wastes in a Photoelectrochemical Cell. The concept of the Photofuelcell: A Review of a Re-Emerging Research field, J. Hazard. Mater., 2011, 185, [11] E. Kalamaras, P. Lianos, Current Doubling effect revisited: Current multiplication in a PhotoFuelCell, Journal of Electroanalytical Chemistry, 2015, 751(15), [12] S. Karuppuchamy, M. Iwasaki, H. Minoura, Electrochemical Properties of Electrosynthesized TiO2 Thin Films, Appl. Surf. Sci., 2006, 253, [13] R. Michal, S. Sfaelou, P. Lianos, Photocatalysis for Renewable Energy Production Using PhotoFuelCells, Molecules, 2014, 19, [14] S. Kambe, S. Nakade, T. Kitamura, Y. Wada and S. Yanagida, Influence of the Electrolytes on Electron Transport in Mesoporous TiO2 Electrolyte Systems, J. Phys. Chem. B, 2002, 106 (11), [15] L.-C. Pop, S. Sfaelou, P. Lianos, Cation adsorption by mesoporous titania photoanodes and its effect on the current-voltage characteristics of photoelectrochemical cells, Electrochimica Acta, 2015, 156, [16] P. V. Kamat, Quantum Dot Solar Cells. Semiconductor Nanocrystals as Light Harvesters, J. Phys. Chem. C, 2008, 112 (48), [17] R. Nakamura, S. Makuta and Y. Tachibana, Electron Injection Dynamics at the SILAR Deposited CdS Quantum Dot/TiO2 Interface, J. Phys. Chem. C, 2015, 119 (35), [18] M. Antoniadou, D. I. Kondarides, D. D. Dionysiou, and P. Lianos, Quantum Dot Sensitized Titania Applicable as Photoanode in Photoactivated Fuel Cells, J. Phys. Chem. C, 2012, 116, [19] R. Zhou, Q. Zhang, J. Tian, D. Myers, M. Yin, G. Cao, Influence of Cationic Precursors on CdS Quantum-Dot-Sensitized Solar Cell Prepared by Successive Ionic Layer Adsorption and Reaction, J. Phys. Chem. C,,,. [20] K. C. Preetha, K. V. Murali, A. J. Ragina, K. Deepa, A. C. Dhanya, T. L. Remadevi, The role of Cationic Precursors in Structural, Morphological and Optical Properties of PbS Thin Films, IOP Conf. Ser.: Mater. Sci. Eng., 2013, 43, , doi: / x/43/1/

177 [21] N. Balis, V. Dracopoulos, K. Bourikas, P. Lianos, Quantum dot sensitized solar cells based on an optimized combination of ZnS, CdS and CdSe with CoS and CuS counter electrodes, Electrochim. Acta, 2013, 91, [22] M. Antoniadou, V. M. Daskalaki, N. Balis, D. I. Kondarides, C. Kordulis, P. Lianos, Photocatalysis and photoelectrocatalysis using (CdS-ZnS)/TiO2 combined photocatalysts, Applied Catalysis B: Environmental, 2011, 107(1 2), [23] S. Sfaelou, M. Antoniadou, G. Trakakis, V. Dracopoulos, D. Tasis, J. Parthenios, C. Galiotis, K. Papagelis, P. Lianos, Buckypaper as Pt-free cathode electrode in photoactivated fuel cells, Electrochimica Acta, 2012, 80, [24] S. Sfaelou, X. Zhuang, X. Feng, P. Lianos, Sulfur-doped porous carbon nanosheets as high performance electrocatalysts for PhotoFuelCells, RSC Adv., 2015, 5,

178 ά 5 ί ί ή έ ά ό ό ώ

179 ή,, [1].,, S/Na2S Na2S/Na2SO3., 2, S/Na2S S2 2-., Na2S/Na2SO3. Ω TiO2, (CuS, CoS, Cu2S) ο.. ό ί ό.. ό ί ά ά (DRS)., TiO2 (CdS/TiO2,CdSe/CdS/TiO2, ZnS/CdSe/CdS/TiO2). [2].,

180 400 C CdS Silar Cd(NO3)2. CdS /TiO2,., CdSe/CdS /TiO2. CdSe, [2]. ZnS/CdSe/CdS /TiO2. ή 5.1: ά ά ά ί CdS/TiO2, CdSe/CdS/TiO2 ZnS/CdSe/CdS/TiO2: ί έ, ό έ C ό ό ή ό έ C ί N2. ό ό ά ή ύ ί ί ά

181 Ό, TiO2 CdS CdS Silar., CdSA/TiO2 PbS. 5.2a CdS/TiO2, CdSA/PbS/TiO2 5.2b. PbS/TiO2 800 nm PbS.,., CdS PbS/TiO2 CdS PbS [3,4]., DRS, (CdS /PbS/TiO2) PbS,.,,

182 ή 5.2: ά ά ά (a) ί CdS/TiO2 έ ύ ή ώ ό ώ Cd 2+ : (1) Cd(NO3)2, (2) CdSO4, (3) Cd(CH3COO)2 (b) ί : (1) PbS/TiO2, (2) CdSA/PbS/TiO

183 5.1.2 ό ί Raman TiO2 (CdS /TiO2, CdSe/CdS /TiO2, ZnS/CdSe/CdS /TiO2), Raman Micro-Raman. Ό Raman, 5.3. Ω TiO2., 143 cm -1. CdSN, CdS cm -1. CdSe, CdS. Ό, CdSe CdSxSe1-x CdSN CdSe., ZnS., Micro-Raman 5.4. CdSN/TiO2, CdS,. CdS [5]., Silar,, [6]. CdSe, ZnS [7],

184 ZnS. ή 5.3: ά Raman ί TiO2 ά ά ί ή ώ ώ

185 ή 5.4: ά Micro-Raman ί TiO2 ά ά ί ή ώ ώ, ύ ό ό.. ό ώ ό ό ώ (CuS, CoS) FTO Cu2S. CoS FTO., Ό CuS/FTO, SEM

186 CoS. ή 5.5: ό SEM ό ί CoS/FTO ( ά ό CuS/FTO ά ό. ί ί m nm ί

187 Cu2S,. [8,9]. Ό SEM Cu2S ( 5.6),., Π. EDX ( 5.7) S/Cu ½

188 ή 5.6: ό SEM ( ό Cu2S ό ύ ί ί (a) m (b) 200 nm. ή 5.7: ά EDX ό ό ί ό ό S/Cu ί έ ί 36/

189 5.2.2 ό Cu2S ί ί Cu2S,, XRD. 5.8 Cu Cu2S S. intensity (a.u.) Cu Cu 2 S Cu degree ή 5.8: ά XRD Cu2S ό ή ί ύ ί. 5.3 ί ό έ ύ ΒιΣ έ ΒιΣ/ΤξO2 Ό, CdS TiO2 Silar, Cd 2+ (Cd(NO3)2, CdSO4 Cd(CH3COO)2). 5.9 Π 5.1,

190 . Ό, TiO2. CdS,. Έ, CdS. ( 5.10).,.,. [10]. ή 5.9: ά ύ - ά ί ί ή ά: ά : nc-tio2, (2) CdSN/ nc-tio2, (3) CdSS/ nc- TiO2, (4) CdSA/ nc-tio2, ό : Cu2S, ύ : 1.0 M Na2S/1.0 M S

191 ί. : έ ύ ύ, ά ύ ώ, ά ή ό ό ώ ύ ή 5.9. JSC (ma/cm 2 ) VOC (Volts) F.F. ό % TiO ό ά Cd 2+ Cd(NO3) CdSO Cd(CH3COO) ή 5.10: έ ώ έ ί nc-tio2 FTO ί CdS/nc-TiO2/FTO έ έ ή ώ ό ά Cd 2+ έ ά ή ύ, ό ύ ύ ό ά

192 -, (IPCE%) CdSA/TiO2. DRS 5.11.,. ή 5.11: ύ ά ά ά CdS /TiO2 ό ή ί ύ IPCE ύ έ ά, Cu2S ό ό ύ

193 5.4 Μ έ ώ ώ ώ έ TiO2.. έ ZnS/CdSe/CdS/TiO2 ά ά ί TiO2 [11].,,,. Έ, (.. CdSe, PbS, ZnSe). Έ, CdS, CdSe ZnS [12]. TiO2 (CdS/TiO2,CdSe/CdS/TiO2, ZnS/CdSe/CdS/TiO2) , 5.11 Π 5.2. TiO2,, UV. Έ, ZnS/CdSe/CdS/TiO2, ZnS, (2 Silar). (0.53Π0.59 V),, TiO

194 TiO2, (0.38 V) Φ [13]. ή 5.12: ά ύ - ά ί ή ά: ά : ΤξO2/FTO, (2) CdS/TiO2/FTO, (3) CdSe/CdS/TiO2/ΕΤO ZσΣ/ΒιΣκ/ΒιΣ/ΤξO2/ΕΤO, ό : Cu2S/ ί, ύ : 1 M Na2S/1 M S. ά ά έ ό ύ ά ά -1)

195 ί 5.2: έ ύ ύ, ά ύ ώ, ά ή ό ό ώ ύ ή JSC VOC ό ά (ma/cm 2 ) (Volts) F.F. (%) TiO2/FTO CdS/TiO2/FTO CdSe/CdS/TiO2/FTO ZnS/CdSe/CdS/TiO2/FTO ZnS/CdSe/CdS/TiO2 IPCE. 5.13, IPCE

196 ή 5.13: ύ ά ά ά ί ZnS/CdSe/CdS/TiO2 ό ή ί ύ IPCE) ύ έ ά, Cu2S ό ό ύ., ( 5.14). Raman. TiO2. (ZnS/CdSe/CdS/TiO2)., ZnS,, CdS/TiO2. Ό, ZnS

197 (CdS CdSe)., Η Θ /, [7] J sc (ma cm -2 ) Time (min) ή 5.14: ί ό ό ή ύ ύ ύ ή ά: ά : TiO2/FTO, (2) CdS/TiO2/FTO, (3) CdSe/CdS/TiO2/ΕΤO ZnS/CdSe/CdS/TiO2/ΕΤO, ό : Cu2S/ ί, ύ : 1 M Na2S/1 M S

198 5.4.2 ί έ ό ώ Ό, [3]., TiO2, CdS/TiO2,,.,.., CdSe/CdS/TiO2 ZnS/CdSe/CdS/TiO2., CdSe/CdS/TiO2, 300 C 400 C. Ό,, [2]., CdSxSe1 x Raman VOC. ZnS/CdSe/CdS/TiO C. [14]

199 ή 5.15: ά ύ - ά ί ή ά: ά : a) CdS/TiO2, (b) CdSe/CdS/TiO2 (c) ZnS/CdSe/CdS/TiO2 έ ί ί ώ ί : (1) 100 C, (2) 200 C, (3) 300 C, (4) 400 C, ό : Cu2S/ ί, ύ : 1 M Na2S/1 M S., ( 5.16). CdS/TiO2, -,., Φ 100 C.,.,

200 ., ZnS [14]. ή 5.16: ύ ύ ύ ά ό ό ά ή ά: ά : a) CdS/TiO2, (b) CdSe/CdS/TiO2 c) ZnS/CdSe/CdS/TiO2 ί : (1) έ ί έ, (2) 400 C έ έ, C έ ά, ό : Cu2S/ ί, ύ : M Na2S/1 M S

201 CdS PbS. Ό, PbS 850 nm,., PbS,., CdS PbS TiO2. CdS PbS /, CdSA [3,15,16] (PbS/TiO2 CdS /TiO2) PbS CdS. PbS/TiO2,. CdS TiO2 PbS/TiO2. CdS /TiO2 5 Silar CdS. CdS /PbS/TiO2 15 ma/cm 2.,,

202 ή 5.17: ά ύ - ά ί ή ά: ά : PbS/TiO2 (2 ύ Silar), (2) CdS /TiO2 (5 ύ Silar), (3) CdS /PbS/TiO2, ό : Cu2S/ ί, ύ : M Na2S/1 M S. ή 5.18: ά ί (a ί PbS ά TiO2 b ά ό CdS /PbS/TiO2. ή ί ί ph 13.0 (-0.77 vs SHE)

203 , CdSA PbS PbS/TiO2 80% CdSA 25%. ή 5.19: ύ ό ύ ά ό ό ά ή ά: ά cm 2 ): (1) PbS/TiO2, (2) CdS /PbS/TiO2, ό : Cu2S/ ί, ύ : M Na2S/1 M S

204 . Μ έ ώ ώ, Cu2S., CoS/FTO CuS/FTO,.,. Cu2S, Cu2S. Π 5.3 (RS) / (RCT) 5.20 Nyquist Cu2S.,,., RCT 1153 Cu2S 2.3. Cu2S. Ό CoS/FTO CuS/FTO, RS RCT Cu2S/

205 ί 5.3: έ ή έ ή ά ί ί. ό Rs (Ohm) Rct (Ohm) ί Cu2S/ ί CoS/FTO [17] CuS/FTO [17] 19 6 RS: ω ή α ί α η RCT: α ί α η α ά ί η ά α η ί /η ύ η ή 5.20: ά ί ή έ ό ί ύ ό ύ ί ή ή (2) ό ή ί ό Cu2S ό ύ. έ ά ί έ έ έ ί

206 / Cu2S/.., (+1.5 V -1.5 V) Pt (0.01 Na2S/0.01 S 1.0 Na2S/1.0 S). Ό, V V. Cu2S., V ( ) Cu2S

207 ή 5.21: ά ή ί ί ώ ό ί Cu2S/ ί, ό έ ύ Pt έ ό Ag/AgCl ό ά. ύ ή ά ί ή :. Νζ2Σ/. Σ (2). Νζ2Σ/. Σ., ZnS/CdSe/CdS/TiO , Π CuS/FTO (3.5%).,, Cu2S

208 ή 5.22: ά ύ - ά ί ή ά: ά : ZnS/CdSe/CdS/TiO2, ό : (1) CuS/FTO, (2)CoS/FTO (3) Cu2S/ ί, ύ : 1 M Na2S/1 M S. ί 5.4: έ ύ ύ, ά ύ ώ, ά ή ό ό ώ ύ ή ά ό J (ma/cm 2 ) V (Volts) FF (%) ZnS/CdSe/CdS/TiO2 CuS/FTO ZnS/CdSe/CdS/TiO2 CoS/FTO ZnS/CdSe/CdS/TiO2 Cu2S/brass

209 Na2S/Na2SO3. Ω TiO2, Pt/CC Cu2S/ Ό,. ZnS/CdSe/CdSN/TiO2. Current Density (ma/cm 2 ) A 2B 3B 3A 1A 1B -1,5-1,0-0,5 0,0 0,5 1,0 V (Volts) vs. Ag/AgCl ή 5.23: ά ύ - ά ώ ύ ώ ί ή ί ά Ag/AgCl) ή ά: ά : TiO2, (2) CdSN/TiO2, (3) ZnS/CdSe/CdSN/TiO2, ό : Pt/CC, (B) Cu2S/ ί, ύ : 0.25 M Na2S/0.125 M Na2SO

210 , Cu2S/ Pt/CC., [18,19]. Ά, Pt., TiO2. Π 5.5. Ό 0 V 0.5 V. Ό,., 0.5 V. ί 5.5: έ ό ή ό ώ έ ό, ό Cu2S/ ί ύ 0.25 M Na2S/0.125 M Na2SO3. ά ά ό ά (Volts) Μέ ό ή ό ( mol/min) nc-tio2/fto CdS/nc-TiO2/FTO ZnS/CdSe/CdS/nc-TiO2/FTO

211 ί [1] J. Schneider and D. W. Bahnemann, Undesired Role of Sacrificial Reagents in Photocatalysis, J. Phys. Chem. Lett., 2013, 4 (20), 3479Π [2] S. Woo Jung, M-A Park, J-H Kim, H. Kim, C-J Choi, S. Hyung Kang, K-S Ahn, Two-step annealed CdS/CdSe co-sensitizers for quantum dotsensitized solar cells, Current Applied Physics 13 (2013) [3] D. Punnoose, C. S. S. Pavan Kumar, H. Woong Seo, M. Shiratani, A. Eswar Reddy, S. Srinivasa Rao, C. V. Thulasi-Varma, S-K Kim, S-H Chunga and H-J Kim, Reduced recombination with an optimized barrier layer on TiO2 in PbS/CdS core shell quantum dot sensitized solar cells, New J. Chem., 2016, Advance Article, DOI: /C5NJ02947C [4] Y. Li, L. Wei, X. Chen, R. Zhang, X. Sui, Y. Chen, J. Jiao and L. Mei, Efficient PbS/CdS co-sensitized solar cells based on TiO2 nanorod arrays, Nanoscale Research Letters, 2013, 8:67, DOI: / X-8-67 [5] A.G. Kontos, V. Likodimos, E. Vassalou, I. Kapogianni, Y.S. Raptis, C. Raptis, P.Falaras, Nanostructured titania films sensitized by quantum dot chalcogenides,nanoscale Res. Lett. 2011, 6, 266. [6] R. Ahmed, G. Will, J. Bell, H. Wang, Size-dependent photodegradation of CdSparticles deposited onto TiO2mesoporous films by SILAR method, J. Nanopart.Res., 2012, 14, 1140Π1153. [7] N. Guijarro, J.M. Campina, Q. Shen, T. Toyoda, T. Lana-Villarreal, R. Gómez,Uncovering the role of the ZnS treatment in the performance of quantum dotsensitized solar cells, Phys. Chem. Chem. Phys. 2011, 13, 12024Π [8] S. Gimenez, I. Mora-Sero, L. Macor, N. Guijarro, T. Lana-Villarreal, R. Gomez. L. J. Diguna, Q. Shen, T. Toyoda and J. Bisquert, Improving the performance of colloidal quantum-dot-sensitized solar cells, Nanotechnology, 2009, 20, (6pp). [9] X. Huang, S. Huang, Q. Zhang, X. Guo, D. Li, Y. Luo, Q. Shen, T. Toyoda and Q. Meng, A flexible photoelectrode for CdS/CdSe quantum dot-sensitized solar cells (QDSSCs), Chem. Commun., 2011,47, [10] R. Zhou, Q. Zhang, J. Tian, D. Myers, M. Yin, G. Cao, Influence of Cationic Precursors on CdS Quantum-Dot-Sensitized Solar Cell Prepared

212 by Successive Ionic Layer Adsorption and Reaction. J. Phys. Chem. C 2013, 117, [11] N. Balis, V. Dracopoulos, K. Bourikas, P. Lianos, Quantum dot sensitized solarcells based on an optimized combination of ZnS, CdS and CdSe with CoS andcus counter electrodes, Electrochim. Acta, 2013, 91, 246Π252. [12] Q. Shen, J. Kobayashi, L. J. Diguna and T. Toyoda, Effect of ZnS coating on the photovoltaic properties of CdSe quantum dot-sensitized solar cells, J. Appl. Phys., 2008, 103, [13] S. Sfaelou, A. G. Kontos, P. Falaras, P. Lianos, Micro-Raman, photoluminescence and photocurrent studies on thephotostability of quantum dot sensitized photoanodes, Journal of Photochemistry and Photobiology A: Chemistry, 2014, 275, 127Π 133. [14] S. Sfaelou, A. G. Kontos, L. Givalou, P. Falaras, P. Lianos, Study of the stability of quantum dot sensitized solar cells, Catalysis Today, 2014, 230, 221Π226. [15] A. Braga, S. Giménez, I. Concina, A. Vomiero and. Mora-Seró, Panchromatic Sensitized Solar Cells Based on Metal Sulfide Quantum Dots Grown Directly on Nanostructured TiO2 Electrodes, J. Phys. Chem. Lett., 2011, 2 (5), 454Π460. [16] V. González-Pedro, C. Sima, G. Marzari, P. P. Boix, S. Giménez, Q. Shen, T. Dittrich and I. Mora-Seró, High performing PbS Quantum Dot Sensitized Solar Cells exceeding 4% efficiency: The role of metal precursor in the electron injection and charge separation, Phys. Chem. Chem. Phys., 2013,15, [17] N. Balis, V. Dracopoulos, K. Bourikas, P. Lianos, Quantum dot sensitized solar cells based on an optimized combination of ZnS, CdS and CdSe with CoS and CuS counter electrodes, Electrochimica Acta, 2013, 91, 246Π252. [18] G. Hodes, J. Manassen and D. Cahen, Electrocatalytic Electrodes for the Polysulfide Redox System, J. Electrochem. Soc., 1980, 127 (3), [19] I. Mora-Seró, S. Gimenez, T. Moehl, F. Fabregat-Santiago, T. Lana- Villareal, R. Gomez and J. Bisquert, Factors determining the photovoltaic performance of a CdSe quantum dot sensitized solar cell: the role of the

213 linker molecule and of the counter electrode, Nanotechnology, 2008, 19, (7pp)

214 ά 6 ί ύ ή ή ό

215 ή,, TiO2. WO3 BiVO4. WO3 n ev 500 nm., ph [1,2]. Ό BiVO4, ( 2.8 ev), [3,4]. ( WO3) TiO2. Ό, 2 2 (1.23 V vs. NHE ph=0) + 2 (0 V vs. NHE ph=0).,

216 6.1 ό ώ ΧO3 ΑξΦO4 WO3 BiVO4. Ό SEM 6.1, WO nm., BET 25.4 m 2 /g. TiO2 (Degussa P25) m 2 /g. ή 6.1: ό SEM ά ί WO3 ή ά

217 Ό BiVO4,, Triton X SEM BiVO4 FTO 0.1 g/ml Triton X nm. ή 6.2: ό SEM ά ί BiVO4 ί ά ή. g/ml Triton X-100 ύ ό ά. Π. WO3, 6.3. FTO WO3 25 nm Scherrer. SEM

218 ή 6.3: ά ί ί ΧO3 έ ί FTO. XRD BiVO4 Triton X-100. sol-gel BiVO4. 6.4, Π 6.1. BiVO4, Triton X-100 Bi4V2O g/ml Triton X-100,

219 ή. : ά XRD ί BiVO4 έ ί ή ώ ώ ύ Triton X-100 ό ά. έ έ ί X ύ ί ή ό ύ ό ύ ό ό Bi4V2O11., - Π 6.1., m 2 /g TiO2 Degussa P-25 (45-50 m 2 /g).. Triton X g/ml Triton X

220 ί. : ά ά BiVO4 ά ώ έ ώ ύ TritonX-100. έ Μέ SBET ά ά Ό Triton X-100 ί (m 2 /g) ό ό ό (g/ml) (nm) (nm) (nm) (cm 3 /g) ,.,, Triton X-100 (0.025 g/ml)., 6.5. UV., WO3 465 nm, BiVO4 505 nm

221 ή 6.5: ά ά ά ί WO3 BiVO4 έ FTO. 6.2 έ ή ή ύ ό WO3,,.,. 6.6.,., 1.6 V

222 vs Ag/AgCl ( onset 2.0 V vs Ag/AgCl) 3.5 ma/cm ma/cm 2. ή 6.6: ά ύ - ά ί ί έ ά WO3, ό έ ύ Pt ύ. NaClO4 : ή ό ό ό : ί ό έ ί 5% v/v ό. Ό,, [5]. onset 0.3 V vs Ag/AgCl. onset -0.2 V vs Ag/AgCl, Na

223 ,. NaClO4 LiClO4. Ό ( 6.7), LiClO4, Li + Na +, WO3 [6]. ή 6.7: ά ή ί ύ ώ ί ή Ag/AgCl ό ά ί έ ά WO3, ό έ ύ Pt ύ. NaClO4 ή. LiClO4. ύ ά έ ί ή ό

224 TiO2, - ( 4.5 mg/cm 2 ). ( 6.8). WO3.., TiO2, onset WO3. WO3 IPCE ( 6.9). ή 6.8: ά ύ - ά ύ ώ ί ή Ag/AgCl ό ά ί ί ή ά: ά :, WO3, TiO2, ό : ύ Pt, ύ :,. NaClO4,. NaClO4 + 5% v/v EtOH

225 ή 6.9: ά ά ά ύ WO3 έ IPCE%. έ IPCE ή ή ή ά 1.6 V vs Ag/AgCl., WO V vs Ag/AgCl 1.6 V vs Ag/AgCl FTO. 5% v/v.,., 20 [7]

226 ή 6.10: ή ή ό mol/min) ή ή ό (mmol) ί έ ά WO3 ό ί FTO ί ί ί ή ά ά ί ύ. ά ό ά ί 1.0 V vs Ag/AgCl ή. V vs Ag/AgCl

227 BiVO4, (Triton X-100),., Triton X-100: 0.025, g/ml ή 6.11: ά ύ - ά ύ ώ ί ή ί Ag/AgCl ό ά ί ί BiVO4 ά, έ ύ ύ ό. NaHCO3 ύ. ά έ ί ή ό ύ Triton X-100: ή ό, g/ml, (3) 0.05 g/ml (4) 0.1 g/ml. Ό ά ά ά RHE έ ό έ ί ά ά ό έ : V(Volts) = x(pH), ό 0.2 ί ό Ag/AgCl vs. SHE ί ή ph ύ NaHCO3 ί