Active Sites for CO₂ Hydrogenation to Methanol: Mechanistic Insights and Reaction Control

Catalytic CO₂ conversion to methanol is a promising way to extenuate the adverse effects of CO₂ emission, global warming and energy shortage. Understanding the fundamental features of CO₂ activation and hydrogenation at the molecular level is essential for carbon utilization and sustainable chemical production in the current climate crisis. This review explores the recent advances in understanding the design of catalysts with desired active sites, including single-atom, dual-atom, interface, defects/vacancies and promoters/dopants. We focused on the design of various catalytic systems to enhance their catalytic performances by stabilizing active metal in a catalyst, identifying the unique structure of active species, and engineering coordination environments of active sites. Mechanistic insights provided by advanced operando and in situ spectroscopies were also discussed. Moreover, the review highlights the key factors affecting active sites and reaction mechanisms, such as local environments, oxidation states, and metal-support interactions. By integrating recent advancements and relating knowledge gaps, this review aims to endow an inclusive overview of the field and guide future research toward more efficient and selective catalysts for CO₂ hydrogenation to methanol.