Progress of In₂O₃-based catalysts in thermal catalytic CO₂ hydrogenation reaction

Catalytic hydrogenation of CO₂ is considered to be one of the most practical ways to produce value-added chemicals and fuels. However, due to the extreme chemical inertness, the high C–C coupling barrier and the many competing reactions, it is of vital important to develop the efficient catalysts for achieving the activation and transformation of CO₂ into a variety of chemical products. In recent years, indium oxide has aroused great interest in CO₂ hydrogenation due to its abundant oxygen vacancies, high selectivity of methanol and high activity of CO₂ conversion. In this paper, the structure of In₂O₃ and the catalytic performance of In₂O₃-supported or metal-doped composite catalysts for CO₂ hydrogenation to methanol are reviewed. The effects of the proximity of In₂O₃ to different zeolites and the migration of elements on the products of CO₂ hydrogenation to hydrocarbons are also discussed. Finally, the challenges and development directions of selective hydrogenation of CO₂ over In₂O₃-based catalysts are summarized.