Highly selective production of ethane from CO₂ hydrogenation using 2D MoS₂ catalyst under photothermal catalysis

Under the combined push of global climate governance and the “dual-carbon” goal, research on CO₂ catalytic conversion has attracted great attention. In recent years, photothermal catalysis, as an emerging catalytic technology, can not only enhance the utilization of solar energy but also convert light energy into heat, increasing the reaction temperature and combining the advantages of both photocatalysis and thermocatalysis. Therefore, it has become one of the research hotspots for CO₂ hydrogenation reactions. However, photothermal catalytic CO₂ hydrogenation still faces challenges such as low catalyst activity, limited photothermal efficiency, and difficulty in controlling product selectivity. Furthermore, the main selective products of traditional catalysts are C₁ compounds, and the formation of C₂₊ products involves complex C—C coupling processes that require overcoming high kinetic barriers, resulting in generally low selectivity for C₂ products by conventional catalysts. Therefore, developing catalysts with high activity, high selectivity and photothermal stability is the key to achieving the targeted conversion of CO₂ into C₂ products. A series of MoS₂ catalysts composed of three-dimensional flower-like microspheres self-assembled from ultrathin nanosheets were synthesized by hydrothermal method through regulating the mass ratio of sulfur source and molybdenum source in the precursor. Among them, the MoS₂-1.5 catalyst achieved a C₂H₆ selectivity of 69.2% and a production rate of 253.66 μmol/（g·h） under 1.2 W/cm² light irradiation. Meanwhile, the research results confirmed that by regulating the light intensity and extending the light exposure time, the CO₂ conversion rate and ethane selectivity could be effectively enhanced. Through comparison with thermal catalysis, the significant advantages of higher CO₂ conversion efficiency and product selectivity under photothermal catalysis conditions were highlighted. The excellent stability of MoS₂ demonstrated the unique advantages of two-dimensional sulfides in carbon chain growth reactions, providing a new idea for designing photothermal catalysts that can convert CO₂ into high-value chemicals under mild conditions.