Photocatalytic Activity of Novel Ag_4V_2O_7 Photocatalyst Under Visible Light Irradiation

摘要

In this study, pure Ag_4V_2O_7 was synthesized via hydrothermal method without surfactant at different temperatures (100℃, 120℃, and 140℃) and pH values (4 and 5) for the first time. Moreover, Ag_4V_2O_7 nanoparticles with homogeneous size distribution about 200-300 nm can be obtained by adding polyvi-nylpyrrolidone to the synthesis system. Effects of hydrothermal synthesis conditions on photophysical properties and photocatalytic activity of Ag_4V_2O_7 were investigated systematically. Ag_4V_2O_7 sample prepared at 120℃ and pH ＝ 4 had the optimal photocatalytic activity among these samples, which almost completely degraded 10 ppm Rhodamine B within 3 h under visible light irradiation (420 nm ＜λ＜ 800 nm). The degradation products were measured by liquid chromatography-mass spectroscopy. The active species involved in the degradation process were analyzed by means of adding active species scavengers, electron spin resonance techniques, and photoelectro-chemical experiments. A possible mechanism for photocatalytic degradation of organic pollutants on Ag_4V_2O_7 photocatalyst was proposed and discussed preliminarily.