Tuning the band gap energy of CuxInyS for superior photothermocatalytic CO2 conversion to C2H4

Abstract

Photothermal catalysis significantly enhances the efficiency of photocatalytic CO₂ reduction, offering a promising strategy for accelerated CO₂ resource utilization. Herein, a series of Cu_xIn_yS photocatalysts were synthesized, exhibiting tunable band gap energy by varying the Cu/In/S atomic ratios for photothermocatalytic CO₂ conversion to C₂H₄. The typical CuInS₂ catalyst demonstrates a more negative conduction band, significantly enhancing the electron reduction ability and facilitating the multi-electron reduction of CO₂ to C₂H₄. Additionally, the abundant sulfur vacancies in CuInS₂ generate additional active sites, enhance charge separation efficiency, and consequently improve catalytic activity. The generation rate of ethylene reaches 45.7 μmol g⁻¹ h⁻¹ with a selectivity of 79.7%. This study provides a new avenue for producing ethylene in photothermal catalysis, as well as highlighting the superiorities of the CuInS₂ catalyst.