Ru-In2O3/g-C3N4 photothermal coupling catalyzed boosted carbon dioxide hydrogenation to methanol

Abstract

The concentration of carbon dioxide (CO₂) in the atmosphere has been progressively increasing, resulting in the deterioration of the human living environment. Converting CO₂ into valuable chemical products represents one of the most promising solutions to mitigate these environmental challenges. Among various approaches, the production of methanol from CO₂ and H₂ via photothermal catalysis stands out as an important way for CO₂ resource utilization. Photothermal catalysis combines the advantages of both photocatalysis and thermal catalysis, thereby enhancing CO₂ conversion efficiency and methanol selectivity. In this study, the catalysts Ru-In₂O₃ and Ru-In₂O₃/g-C₃N₄ for converting CO₂ into methanol were prepared by coprecipitation method. More oxygen vacancies were created in In₂O₃ and band gap was narrowed after doping ruthenium. More active sites and better charge separation capability were provided by the addition of g-C₃N₄. When Ru-In₂O₃/1.5 % g-C₃N₄ was used as the catalyst, the methanol space–time yield was up to 114.68 g_MeOH·h^-1·kg_cat^-1, and the catalytic performance tested under photothermal reaction conditions at 265 °C and 1.0 MPa remained stable in 20 h. This work provides a new strategy for promoting the development of CO₂ hydrogenation to methanol under conditions of low temperature and low pressure.