Plasmonic Ag modified Ag3VO4/AgPMo S-scheme heterojunction photocatalyst for boosted Cr(VI) reduction under visible light: Performance and mechanism

Environmental crisis caused by Cr(VI) pollution has gained remarkable attention. Developing efficient photocatalysts for Cr(VI) remediation remains a great challenge. Herein, the Ag@Ag3VO4/Ag3PMo12O40 (Ag@Ag3VO4/AgPMo) S-scheme heterojunctions were prepared via the combination of hydrothermal and photodeposition methods for Cr(VI) reduction. The resultant S-scheme heterojunctions were characterized to investigate their morphological, structural, photoelectrochemical and optical properties. The synergy of surface plasmon resonance (SPR) effect of Ag and S-scheme hetero-structure improved their photo(electro)chemical performance. Upon visible light irradiation, the optimized Ag@Ag3VO4/AgPMo delivered superior photoreduction efficiency (94.8%) of Cr(VI) and stability with a slight loss of the performance (92.8% after 6 cycles). The enhancement of Cr(VI) reduction performance may be ascribed to the extended light absorption range and separation and migration pathway of photo-induced electron-hole pairs confirmed by the proposed photoreduction mechanism. This work not only confirms a highly active catalytic system for the light-driven environmental application, but pave a way for the construction of S-scheme heterojunction photocatalysts.

Automated summary

This study developed Ag@Ag3VO4/AgPMo heterojunctions as efficient photocatalysts for the reduction of Cr(VI). The S-scheme heterostructure exhibited superior performance and stability due to the synergy of the surface plasmon resonance effect of Ag and the S-scheme configuration. The proposed photoreduction mechanism demonstrated extended light absorption range and efficient separation and migration of photo-induced electron-hole pairs. This work not only provides a highly active catalytic system for light-driven environmental applications, but also paves the way for the construction of S-scheme heterojunction photocatalysts.