Effects Of Doping On Surface Photoelectric And Photocatalytic Properties Of Antimoniate

Energy crisis and environment remediation are two important issues today. How to develop and usethe renewable energy and protect environment becomes the hot topics. Semiconducto photocatalytictechnology is used to purify the waste water. The photo-generated electrons and holes in the semiconductorcould decompose the organic compounds and reduce the ions of heavy metals using the redox. The hardworks should be done, although the remarkable achievements have been made in the past four decades.In this study, AgSbO₃and ZnSb₂O₆were modified by doping to improve the photocatalyticperformance of decomposing the organic compounds. The effects of N and transition metals doping wereinvestigated, the surface photoelectric and photocatalytic activity are mainly focused. The main contentsare as followings.（1）The ZnSb₂O₆-based photocatalyst were synthesized by a conventional solid-state reaction method.The samples were characterized by X-ray diffraction （XRD）, UV-vis spectroscopy, surface photovoltagespectroscopy and scanning electron microscopy. The photocatalytic activities of the prepared samples wereevaluated from the degradation of Rhodamine B （RhB） under full arc Xe lamp and visible light irradiation.The XRD and UV-vis results indicated that the N-doping did not change the crystal structure, but decreasethe band gap in comparison with the pristine one. The N-doped ZnSb₂O₆shows the reduced surfacephotovoltage signals and the significant enhanced photocatalytic activity under two irradiations.（2） The AgSbO₃and Nb-AgSbO₃photocatalyst with different doping amount of Nb were synthesizedby a conventional solid-state reaction method. The samples were characterized by X-ray diffraction （XRD）,UV-vis spectroscopy, surface photovoltage spectroscopy and scanning electron microscopy. Thephotocatalytic activities of the prepared samples were evaluated from the degradation of Rhodamine B（RhB） under visible light irradiation. It indicated that the Nb ions have entered into the lattice of AgSbO₃.With the doping amount increases, the particle size of Nb-AgSbO₃becomes larger, its optical band gap andthe surface photovoltage reduced sequentially. But the curve of photocatalytic performance was against tothe horizontal cast. The degradation results indicate that appropriate Nb-doped can effectively enhance the visible light catalytic activity of AgSbO₃and doping exists the best quantity, value of x=0.06-0.09.（3） The AgSbO₃and M-AgSbO₃photocatalyst with different doping elements （Ti, V, Nb, Ta, W） weresynthesized by a conventional solid-state reaction method. The samples were characterized by X-raydiffraction （XRD）, UV-vis spectroscopy, surface photovoltage spectroscopy and scanning electronmicroscopy. The photocatalytic activities of the prepared samples were evaluated from the degradation ofRhodamine B （RhB） under full arc Xe lamp and visible light irradiation. The study shows that the metalions have been doped into the AgSbO₃lattice. With the different doping elements, the crystallinity, thesurface morphology, the optical band gap, the photocatalytic performance were different. The results showthat it enhanced the visible light photocatalytic activity of AgSbO₃with appropriate doping transition metalelements from the degradation of modamine B solution.