In-situ generation of Bi0 NCs and vacancies on Bi-CTS/BiOBr heterostructures accelerate electron transfer for promoting photocatalytic reduction of CO2

Developing high-efficiency photocatalysts for CO 2 conversion remains a challenge. Herein, S-scheme Bi-Cu 3 SnS 4 /BiOBr heterojunction with S, O defective vacancies was successfully prepared by hydrothermal process and NaBH 4 reduction method. Characterization results showed that the Cu 3 SnS 4 nanoparticles were uniformly dispersed onto the BiOBr nanosheets, with Bi 0 nanoclusters (NCs) serving as a bridge between the BiOBr and Cu 3 SnS 4 .The S-scheme heterojunction was demonstrated via ultraviolet photoelectron spectrometer (UPS) work function. The surface plasma resonance (SPR) effect of Bi 0 NCs, the internal electric field (IEF) and S, O defects coregulation of Fermi level equilibrium enhanced light utilization and facilitated photogenerated carriers’ separation, resulting in superior photocatalytic activity. Under visible light illumination, the Bi-Cu 3 SnS 4 /BiOBr (30) achieved CO yield of about 50.13 μmol·g -1 ·h -1 within 120 min, which was 3.5 times of pristine Cu 3 SnS 4 (15.6 μmol·g -1 ·h -1 ). Moreover, it exhibited the highest incident photon-electron conversion efficiency (10.58% at 380 nm). This study could provide a reference for designing efficient S-scheme heterojunctions for photocatalytic reduction of CO 2 . • The Bi-Cu 3 SnS 4 /BiOBr heterojunction with S, O vacancies was successfully prepared. • SPR effect of Bi and S, O defects improved photocatalytic activity of CO 2 to CO. • The CO 2 reduction mechanism over the Bi-Cu 3 SnS 4 /BiOBr composite was discussed.