Carbon dioxide conversion to methanol on a PdCo bimetallic catalyst

Abstract

The CO₂ conversion to methanol (CO₂-to-CH₃OH conversion) is a promising way to resolve greenhouse gas emissions and global energy shortage. Many catalysts are of interest in improving the efficiency of the conversion reaction. The PdCo alloy is a potential catalyst, but no research is available to clarify the CO₂-to-CH₃OH reaction mechanism of this alloy. Here, using density functional theory combined with the thermodynamic model, we elucidated the reaction mechanism of the CO₂-to-CH₃OH conversion on the Pd-skin/PdCo alloy catalyst via thermo- and electro-catalytic processes. The adsorption of CO₂-to-CH₃OH intermediates with key stable intermediates such as HCOO, COOH, and CO was explored. Free-energy diagrams for the CO₂-to-CH₃OH conversion were constructed. We found that the formate pathway is the most favorable one. The charge transfer plays a crucial role in the substrate–adsorbate interaction via electronic structure analysis. This work provides valuable guidance for designing Pd-based catalysts for the CO₂-to-CH₃OH conversion.