Local charge rectification and electronic interactions in ZnIn2S4-x-Bi2MoO6-x heterojunction for enhancing synergistic piezo-photocatalytic hydrogen evolution and benzylamine oxidation

The synergistic utilization of vacancies and heterojunctions in piezo-photocatalysis holds great promise for mitigating the issue of charge recombination. However, the charge aggregation effect in vacancies and the disordered positive and negative charge centers in piezoelectric materials may potentially compromise the performance of synergistic piezo-photocatalysis. Here, the well-designed dual vacancies of ZnIn2S4-x and BiMoO6-x S-scheme heterojunction (BZ) was prepared for synergistic piezo-photocatalytic amines coupling to generate imines integrated with H2 production. Impressively, BZ-2 demonstrated an efficient N-benzylidenebenzylamine production rate of 4680 µmol g-1 h-1 and H2 formation rate of 4480 µmol g-1 h-1 without using any solvent or cocatalyst, where the formation rate of H2 is 10.25 times greater than that of ZnIn2S4-x. Experimental data and DFT calculations demonstrated that the presence of dual vacancies induces the formation of an interfacial Bi-S bond, which effectively regulates electronic interactions and rectifies charge disorder at the surface of the S-scheme heterojunction. Furthermore, this interfacial Bi-S bond acts as a strain center for providing a substantial electric field to drive charge transfer. Additionally, the electronic structural coupling contributes to lowering the activation energy and enhancing the reaction kinetics. This study offers profound insights into the relationship between atomic defects and S-scheme heterojunctions in piezo-photocatalysis, facilitating the design of high-efficiency materials.