In-situ green topotactic synthesis of a novel Z-scheme Ag@AgVO3/BiVO4 heterostructure with highly enhanced visible-light photocatalytic activity.

In this work, a novel plasmonic Z-scheme Ag@AgVO3/BiVO4 heterostructure was developed by a topotactic ion exchange-reduction strategy followed with an in-situ growth process. The ternary heterostructure were composed of AgVO3 nanobelts (NBs) loading with BiVO4 nanosheets (NSs) and Ag nanoparticles (NPs), which grew in-situ on the surface of AgVO3 NBs via an topotactic transformation with the assistance of polyvinylpyrrolidone (PVP). Besides, PVP can not only realize the recycle of noble metal Ag but also induce a SPR effect in the composite. Experimental results indicated that the Ag@AgVO3/BiVO4 composites displayed an significantly enhanced photocatalytic activity under visible light irradiation compared to AgVO3, Ag@BiVO4 and AgVO3/BiVO4. The BiVO4 content in the composite played a key role in controlling the morphology and photocatalytic activity of Ag@AgVO3/BiVO4 heterostructure. Among the as-prepared photocatalysts, Ag@AgVO3/BiVO4-0.2 exhibited the highest photocatalytic performance and stability towards the degradation of rhodamine B (RhB) and disinfection of Escherichia Coli (E. coli). In addition, a possible Z-scheme photocatalytic mechanism was proposed based on the active species trapping experiments, demonstrating that the photogenerated holes (h+) and O2- radicals were the dominating active species. The Z-scheme charge carrier migration mechanism, SPR effect of Ag NPs, large specific surface area combined with the stable heterostructure, resulted in the highly efficient transfer and the separation of photoinduced electrons and holes, which further contributed to the superior photocatalytic activity of Ag@AgVO3/BiVO4. This work is expected to inspire further attempts for the construction of novel Z-scheme photocatalysts with enhanced photocatalytic performances for potential application in the field of energy and environment.