Investigation on kinetic and mechanism of Z-scheme Ag3PO4/ WO3 p-n junction photocatalyst with enhanced removal efficiency of RhB
Semiconductor-based photocatalysis attracts wide attention owing to its ability to directly utilize solar energy for production of solar fuels. Especially, the construction of Z-scheme heterojunction is demonstrated to benefit the photocatalytic performance because of the separation and transfer of the photogenerated charge carriers and well-preserved strong redox ability. In this work, a series of Z-scheme Ag3PO4/WO3 p-n junction photocatalysts were prepared via employing a facile impregnation method. The photocatalyst (Ag3PO4/WO3 p-n junction) presented its enhanced photo-degradation efficiency, such as AW-45, 99.9% could be obtained for RhB (30ppm) by irradiation (λ > 420 nm, 350 W Xenon lamp) in 7 min compared with individual constituents. The degradation rate for AW-45 was 27 times higher than that of commercial powder (P25). The apparent kinetic rate of catalytic degradation was obtained according to the results from the degradation process. The mechanism for electron transferred between Ag3PO4 and WO3 was also investigated. The reduction and oxidation processes concentrated on the CB (conducting band) of Ag3PO4 and the VB (valence band) of WO3, resulting in promoting mechanism for the photocatalytic degradation in the Z-scheme Ag3PO4/WO3 p-n junction photo-catalyst.