High photocatalytic activity of 2D sheet structure ZnO/Bi₂WO₆ Z-scheme heterojunction under simulated sunlight

The ZnO/Bi₂WO₆ sheet structure was synthesized by a simple two-step hydrothermal method, and the structure in which the sheet was in close contact with the sheet improved the photocatalytic performance of Bi₂WO₆. Under simulated sunlight, ZnO/Bi₂WO₆ showed excellent photocatalytic activity for the degradation of phenolic contaminants. The degradation rate of (1:1) ZnO/Bi₂WO₆ to phenol, p-nitrophenol and p-chlorophenol was about 4 times, 7.69 times and 5 times than pure Bi₂WO₆, respectively. The increase in photocatalytic activity is attributed to the Z scheme heterostructure formed by the two semiconductors, which can effectively separate photogenerated carriers. Compared with a single catalyst, ZnO/Bi₂WO₆ exhibits excellent charge transport properties in photoelectric conversion. Trap experiments of active species have shown that h  +  and play a major role in photocatalysis. This study proposes a feasible solution for the treatment of a class of pollutant wastewater. (paper)