Journal of Fuzhou University Natural Science Edition. The preparation and visible - light photocatalysis of Ag 3 PO 4 /TiO x N y

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1 Journal of Fuzhou University Natural Science Edition Vol 39 No 5 Oct 2011 DOI CNKI /N Ag 3 PO 4 /TiO x N y Ag 3 PO 4 /TiO x N y N 2 X - Ag 3 PO 4 TiO x N y TiO x N y Ag 3 PO 4 /TiO x N y BET TiO x N y Ag 3 PO 4 / TiO x N y O643 3 A The preparation and visible - light photocatalysis of Ag 3 PO 4 /TiO x N y ZHENG Hua - rong LIU Chang - an SU Wen - yue WANG Xu - xu Research Institute of Photocatalysis Fuzhou University Fuzhou Fujian China Abstract Ag 3 PO 4 /TiO x N y photocatalysts are prepared by a sol - gel method The physical properties and active species of the as - prepared samples are characterized by N 2 sorption analysis X - ray diffraction XRD UV - Vis diffuse reflectance spectroscopy UV - Vis DRS TPD - MS and ESR Visible - light photocatalytic decomposition of gaseous benzene over the Ag 3 PO 4 /TiO x N y catalysts was investigated The results showed that the catalytic and structural properties of TiO x N y were improved by Ag 3 PO 4 modifying When compared to unmodified TiO x N y the Ag 3 PO 4 /TiO x N y exhibited higher resistance to crystal phase transformation from anatase to rutile bigger BET specific area the red - shifted band edge of adsorption spectra and higher photocatalytic activities because of the adsorption enrichment of benzene and of the effective photogenerated electron - hole pair s separation Keywords TiO x N y Ag 3 PO 4 /TiO x N y visible light photocatalysis benzene TiO TiO ev 3% ~ 4% TiO 2 TiO TiO 2 7 TiO x N y 8 Ag 3 PO 4 Ag 3 PO 4 TiO x N y TiO x N y ml 0 05 mol L ml mol L h 60 Ag 3 PO E - mail suweny@ fzu edu cn J J01033

2 N 32 g L g Ag 3 PO ml N h 0 2 ~ 0 3 mm Ag 3 PO 4 /TiO x N y Ag 3 PO 4 TiO x N y 1 2 Micromeritics ASAP 2020 XRD Bruker D8 Advance X Cu Kα 40 kv 40 ma Varian Carry 500 UV - Vis - DRS BaSO 4 X Quantum 2000 Al Kα C 1s ev Autochem 2910 OmiStar λ > 420 nm - ESR Brucker ESP A DMPO mm 10 mm 2 mm Xe 420 nm < λ < 800 nm 0 32 g ml min h HP6890 Porapak R 20 min CO 2 FID TCD Ag 3 PO 4 X Ag 3 PO 4 TiO x N y TiO TiO x N y Ag 3 PO 4 /TiO x N y TiO 2 Ag 3 PO 4 Ag 3 PO 4 2% Schrereer 2 θ 25 5 TiO x N y Ag 3 PO 4 /TiO x N y TiO nm Ag 3 PO 4 TiO 2 1 Ag 3 PO 4 /TiO x N y TiO x N y XRD 2 Ag 3 PO 4 /TiO x N y TiO x N y Fig 1 XRD patterns of Ag 3 PO 4 /TiO x N y and TiO x N y Fig 2 The nitrogen adsorption - desorption isotherms of Ag 3 PO 4 /TiO x N y and TiO x N y samples 2 Ag 3 PO 4 /TiO x N y TiO x N y ~ 0 35 BET Ag 3 PO 4 TiO x N y BET 34 2 m 2 g m 2 g - 1 Ag 3 PO m 2 g Barrett - Joyner - Halenda BJH Ag 3 PO 4 TiO x N y 0 120

3 5 Ag 3 PO 4 /TiO x N y cm 3 g - 1 Ag 3 PO 4 /TiO x N y 3 Ag 3 PO 4 /TiO x N y TiO x N y TiO x N y DRS Ag 3 PO 4 /TiO x N y Ag 3 PO 4 TiO x N y 3 Ag 3 PO 4 /TiO x N y TiO x N y 4 Fig 3 UV - vis DRS of Ag 3 PO 4 /TiO x N y and TiO x N y Fig 4 Mass spectrum patterns of benzene during the TPD process of samples TPD - MS Ag 3 PO 4 /TiO x N y TiO x N y Ag 3 PO 4 50 mg min 30 min 4 MS 4 Ag 3 PO 4 Ag 3 PO 4 TiO x N y 60 TiO x N y Ag 3 PO 4 /TiO x N y Ag 3 PO 4 TiO x N y 2 2 Ag 3 PO 4 /TiO x N y Ag 3 PO 4 TiO x N y 5 Ag 3 PO 4 /TiO x N y TiO x N y Ag 3 PO 4 Ag 3 PO 4 / TiO x N y 12 h 22 4% CO % CO 2 TiO x N y 7 7% CO 2 Ag 3 PO 4 Ag 5 3 PO 4 /TiO x N y CO 2 XRD XPS Fig 5 The photooxidation of benzene over Ag 3 PO 4 /TiO x N y Ag 3 PO 4 /TiO x N y TiO x N y and Ag 3 PO 4 samples under visible light irradiation Symbols and represent C 6 H DMPO 6 and CO 2 respectively ESR Ag 3 PO 4 /TiO x N y TiO x N y Ag 3 PO 4

4 s ESR 6 6 a Ag 3 PO 4 /TiO x N y TiO x N y DMPO - H 2 O DMPO - OH ESR DMPO - OH Ag 3 PO 4 DMPO - OH 12 6 b DMPO DMPO - O - 2 ESR 10 Ag 3 PO 4 /TiO x N y > Ag 3 PO 4 > TiO x N y TiO x N y Ag 3 PO 4 ESR a DMPO - H 2 O DMPO - OH Fig 6 6 b DMPO DMPO - O2-150 s DMPO spin - trapping ESR spectra after visible light irradiation for 150 s Ag 3 PO 4 /TiO x N y TiO x N y N TiO O - 2 OH Ag 3 PO 4 TiO x N y Ag 3 PO 4 TiO x N y TiO x N y Ag 3 PO 4 Ag 3 PO 4 /TiO x N y Fig 7 7 Ag 3 PO 4 /TiO x N y Proposed mechanism for photodegradation of organic compounds on Ag 3 PO 4 /TiO x N y sample under visible light irradiation

5 5 Ag 3 PO 4 /TiO x N y Ag 3 PO 4 /TiO x N y 12 h Ag 3 PO 4 /TiO x N y 22 4% TiO x N y 3 2 TiO x N y Ag 3 PO 4 Ag 3 PO 4 /TiO x N y 1 Rockafellow E Haywood J Witte T et al Selenium - modified TiO 2 and its impact on photocatalysis J Langmuir Yu Huo - gen Irie H Shimodaira Y et al An efficient visible - light - sensitive Fe III - grafted TiO 2 photocatalyst J J Phys Chem C He Jing - fu Liu Qing - hua Sun Zhi - hu et al High photocatalytic activity of rutile TiO 2 induced by iodine doping J J Phys Chem C Sato S Photocatalytic activity of NO x - doped TiO 2 in the visible light region J Chem Phys Lett Asahi R Morikawa T Ohwakl T et al Visible - light photocatalysis in nitrogen - doped titanium oxides J Science Chen Xiu - fang Wang Xin - chen Hou Yi - dong et al The effect of postnitridation annealing on the surface property and photocatalytic performance of N - doped TiO 2 under visible light irradiation J J Catal Vinodkumar E Michael K Steven J et al Highly visible light active TiO 2 - xn x heterojunction photocatalysts J Chem Mater Yi Zhi - guo Ye Jin - hua Kikugawa N et al An orthophosphate semiconductor with photooxidation propertiyes under visible - light irradiation J Nat Mater Fu Xian - zhi Zeltner W A Yang Qing et al Catalytic hydrolysis of dichlorodifluoromethane CFC - 12 on sol - gel - derived titania unmodified and modified with H 2 SO 4 J J Catal Fu Hong - bo Zhang Li - wu Zhang Shi - cheng et al Electron spin resonance spin - trapping detection of radical intermediates in N - Doped TiO 2 - assisted photodegradation of 4 - chlorophenol J J Phys Chem B Zhao Xu Qu Jiu - hui Liu Hui - juan et al Photoelectrocatalytic degradation of triazine - containing azo dyes at γ - Bi 2 MoO 6 film electrode under visible light irradiation λ > 420 nm J Environ Sci Technol TiO 2 ESR J Irie H Watanabe Y Hashimoto K Nitrogen - concentration dependence on photocatalytic activeity of TiO 2 - xn x powders J J Phys Chem B