Advances in CO2 hydrogenation: Mechanisms and catalysts for alcohol synthesis

The hydrogenation of CO₂ to generate alcohols is a viable strategy for the chemical synthesis and production of sustainable fuels. This approach not only produces beneficial industrial chemicals but also directly lowers CO₂ emissions. In this review, the most recent developments in catalytic systems designed to hydrogenate CO₂ into alcohols are examined, with methanol, ethanol, and higher alcohols being taken as example products. Particular emphasis is placed on heterogeneous catalysts, including their activities, selectivities, and stabilities under various thermodynamic operating conditions. This review focuses on catalysts that are based on transition metals, such as Co, Cu, Fe, Zn, Zr, Ni, and Pd. The roles of promoters and support materials in enhancing the catalyst performances are also investigated. Moreover, the reaction mechanisms involved in these transformations are considered, highlighting the crucial intermediates and reaction pathways that lead to alcohol production. Finally, various challenges are discussed, including catalyst deactivation, the reaction scalability, and the overall energy efficiency, as well as emerging trends such as the incorporation of renewable hydrogen sources. The goal of this article is to provide a comprehensive overview of state-of-the-art catalytic CO₂ hydrogenation protocols to generate alcohols and to identify future research directions for advancing this promising field toward practical applications.