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@Ag 3 VO 4 /Ag 3 PMo 12 O 40 (Ag@Ag 3 VO 4 /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@Ag 3 VO 4 /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.