Unlocking sustainable fuel pathways in thermo-catalytic hydrogenation of CO₂ to ethanol: progress, challenges, and future Prospects

The chemical conversion of carbon dioxide (CO₂) into ethanol has become a key area of focus within C1 chemistry due to its potential for efficient CO₂ utilization. Recent years have seen notable progress in thermal catalytic methods for CO₂-to-ethanol transformation. Despite these advances, challenges such as limited conversion efficiency, poor selectivity, and unwanted by-products in the hydrogenation process remain critical issues. This research focuses on examining the thermodynamic properties of CO₂ hydrogenation to address existing challenges. It assesses the catalytic efficiency of both non-noble metals (e.g., Co, Cu, and Mo) and noble metals (such as Rh, Au, Pt, Pd, and Ir), emphasizing the role of various metal active sites in affecting CO₂ conversion efficiency and the selectivity toward ethanol production. This research provides a comprehensive analysis of the critical reaction conditions for CO₂-to-ethanol conversion, covering factors like temperature, pressure, feed ratio, space velocity, reactor type, and water content. It also elucidates the reaction mechanisms associated with various catalytic systems. The work outlines strategies to enhance both CO₂ conversion efficiency and ethanol selectivity by addressing existing challenges. These findings offer a solid theoretical foundation for designing efficient catalysts, optimizing reaction parameters, deepening the understanding of reaction mechanisms, and advancing the potential industrial-scale implementation of CO₂ hydrogenation for ethanol production.