CuCo₂S₄/g-C₃N_4–<i>x</i> S-Scheme Heterojunction for Photothermal-Assisted Photocatalytic CO₂ Reduction

Photocatalytic conversion of CO₂ into chemical fuels has emerged as a research hotspot, aiming to mitigate the rapid depletion of fossil fuels and alleviate global warming. However, the inherent low carrier separation efficiency and limited solar light utilization of photocatalysts lead to unsatisfactory CO₂ conversion efficiency. In this study, an appealing CuCo₂S₄/g-C₃N_4-<i>x</i> S-scheme heterostructure is successfully fabricated by a simple polyol reflux method. Notably, nitrogen vacancies enhance the Fermi level difference between CuCo₂S₄ and g-C₃N_4-<i>x</i>, resulting in a stronger interfacial built-in electric field. The full-spectrum strong optical absorption capability endows the synthesized catalysts with superior light-harvesting property. The photothermal effect-induced temperature increase accelerates the cyclic process of CO₂ adsorption and CO desorption on the catalyst surface. Most importantly, the S-scheme charge transfer pathway ensures the efficient separation of photogenerated carriers. Thanks to these synergistic benefits, CuCo₂S₄/g-C₃N_4-<i>x</i> exhibits exceptional photothermal-assisted photocatalytic CO₂ reduction performance. Under simulated sunlight, the average CO production rate of CuCo₂S₄/g-C₃N_4-<i>x</i> reaches 24.64 μmol g^-1 h^-1, which is 12.1 and 27.1 times higher than that of g-C₃N₄ and CuCo₂S₄, respectively. This study offers a novel strategy for designing photocatalysts with outstanding CO₂ conversion performance.