Fabrication of BiVO4/BiPO4/GO composite photocatalytic material for the visible light-driven degradation

Because of complex chemical structures, water pollution especially dye pollutants from textile industries has been a rigorous problem. Thereby a new composite photocatalyst BiVO4/BiPO4/GO was successfully synthesized to overcome this situation. Its high photocatalytic performance was attributed to the formation of effective heterojunction between BiVO4 and BiPO4, as well as the excellent electroconductivity of GO. It presented superior photocatalytic activity and completely decomposed the RB-19 dye molecules (99%) within 60 min under visible-light irradiation. And the average photocatalytic rate was 31.5 times that of BiPO4 and 4.9 times that of BiVO4. In addition, the main active species were identified by experimental phenomena, comparative test results and hole-radical capture experiments. The photocurrent signal intensity was much larger than that of the single BiVO4 or BiPO4, BiVO4/BiPO4/GO also has a smaller resistance value, which was beneficial to the transmission of photogenerated carriers. The photoluminescence spectrum (PL) indicated the photogenerated electron hole pairs of BiVO4/BiPO4/GO with superior separation efficiency. The reasonable photocatalytic mechanism for degrading RB-19 was proposed based on trapping experiment. A novel BiVO4/BiPO4/GO/cotton composite catalytic material was prepared, and the degradation rate of which was still as high as 85% after 10 cycles. This work highlighted an excellent photocatalysis system in the practical application of the sewage treatment.