Preparation of a CoS2/g-C3N4 composite catalyst and its application in photocatalytic reduction of CO2†

As a greenhouse gas, CO₂ is also a rich carbon resource. Photocatalytic reduction of CO₂ into usable chemicals using sunlight can not only alleviate the increasingly severe greenhouse effect but also provide a promising method for achieving energy recycling to address the problem of energy shortage. Herein, a CoS₂ cocatalyst was grown on g-C₃N₄ nanosheets by a simple in situ growth method, and the composite catalyst was applied for the photocatalytic reduction of CO₂. In the catalyst, CoS₂ nanoparticles were uniformly distributed on the g-C₃N₄ nanosheets. The g-C₃N₄ nanosheet structure increased the specific surface area of the material, thereby facilitating the exposure of CoS₂ sites. Moreover, as a non-precious metal cocatalyst, CoS₂ could replace some precious metal cocatalysts to improve the separation efficiency of photo-generated charges in g-C₃N₄. The prepared catalyst exhibited efficient and stable photocatalytic performance for the reduction of CO₂ and had high selectivity for CO generation. This work provides new insights into designing a low-cost, high-performance photocatalyst for the photocatalytic reduction of CO₂.