Enhanced photocatalytic performance for CO₂ reduction via an S-scheme heterojunction between perovskite nanocrystals and BiVO₄

This study presents the successful synthesis of an S-scheme heterojunction between aged Cs_0.5FA_0.5PbBr₃ (CF) perovskite nanocrystals and a BiVO₄ semiconductor, aiming to enhance the photocatalytic CO₂ reduction performance. Through meticulous optimization of synthetic methods, material ratios, and the pH of BiVO₄, we achieved a remarkable CO production yield of 865 ± 38 μmol g⁻¹ in 12 h when the CF to BiVO₄ ratio was 15 : 1 and the pH value of the synthesized BiVO₄ was adjusted to 4; the individual CF and BiVO₄ photocatalysts can only produce CO with yields of 270 and 71 μmol g⁻¹, respectively. Characterization techniques including XRD, SEM-EDS, PL, TCSPC, and UPS spectroscopy confirmed the formation of the S-scheme heterostructure and enhanced photocatalytic performance in varied proportions of CF versus BiVO₄. The S-scheme heterojunction photocatalyst effectively inhibited electron-hole recombination, facilitating enhanced charge separation and electron-hole transfer for efficient photocatalytic CO₂ reduction. This research not only rejuvenated the photocatalytic capabilities of aged perovskite materials but also addressed the critical challenge of formation of an S-scheme heterojunction between CF and BiVO₄, offering a promising pathway for future design of efficient photocatalysts for CO₂ reduction.