39 5 2011 10 Journal of Fuzhou University Natural Science Edition Vol 39 No 5 Oct 2011 DOI CNKI 35-1117 /N 20111014 1040 024 1000-2243 2011 05-0769 - 05 Ag 3 PO 4 /TiO x N y 350002 - 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 350002 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 2 1-3 TiO 2 3 2 ev 3% ~ 4% TiO 2 TiO 2 4 - TiO 2 7 TiO x N y 8 Ag 3 PO 4 Ag 3 PO 4 TiO x N y TiO x N y 1 1 1 100 ml 0 05 mol L - 1 250 ml 0 006 mol L - 1 6 h 60 Ag 3 PO 4-9 2011-06 - 24 1969 - E - mail suweny@ fzu edu cn 21033003 2009J01025 2010J01033
770 39 N 32 g L - 1 0 32 g Ag 3 PO 4 100 ml N 500 6 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 284 6 ev Autochem 2910 OmiStar λ > 420 nm - ESR Brucker ESP A300 5 5 - - 1 - - DMPO 1 3 20 mm 10 mm 2 mm Xe 420 nm < λ < 800 nm 0 32 g 200 10-6 20 ml min - 1 12 h HP6890 Porapak R 20 min CO 2 FID TCD 2 2 1 Ag 3 PO 4 X Ag 3 PO 4 TiO x N y TiO 2 1 1 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 2 17 4 10 7 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 05 ~ 0 35 BET Ag 3 PO 4 TiO x N y BET 34 2 m 2 g - 1 101 1 m 2 g - 1 Ag 3 PO 4 0 98 m 2 g - 1 8 Barrett - Joyner - Halenda BJH Ag 3 PO 4 TiO x N y 0 120
5 Ag 3 PO 4 /TiO x N y 771 0 294 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 300 90 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 60 237 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 2 86 10-6 33 1% CO 2 TiO x N y 7 7% 28 10-6 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
772 39 150 s ESR 6 6 a Ag 3 PO 4 /TiO x N y TiO x N y DMPO - H 2 O DMPO - OH ESR 4 1 2 2 1 10-11 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 7 8 - TiO x N y N TiO 2 13 - 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
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