Construction of layer-by-layer g-C₃N₄/Ag/Bi₂WO₆ Z-scheme system with enhanced photocatalytic activity

A highly active Z-scheme layer-by-layer g-C₃N₄/Ag/Bi₂WO₆ system was designed and prepared by a facile in situ growth strategy, which led to superior visible-light photocatalytic efficiency with excellent stability and reusability. The photocatalytic degradation rate of Rhodamine B with CN/Ag/BWO was proved to be 3 times higher than g-C₃N₄ and 4 times higher than Bi₂WO₆, further demonstrating the necessity of the layer-by-layer structure and the suitable electron mediator Ag in Z-scheme system. A probable mechanism for the enhanced photocatalytic efficiency of CN/Ag/BWO system was proposed. The results demonstrated that ·O₂⁻ or direct h⁺ was the primary reactive radicals involved, which confirmed that the Z-scheme mechanism of charge carrier transfer conducted the higher photocatalytic activity. This work provided scientific basis for rational construction of Z-scheme photocatalytic system.