Theoretical insights into lanthanide rare earth single-atom catalysts for electrochemical CO2 reduction

Abstract

The electrochemical reduction of CO₂ (CO₂RR) to generate valuable chemicals and fuels has emerged as a promising approach in mitigating environmental issues and energy crises. Single-atom catalysts (SACs) have attracted widespread attention in electrochemical CO₂ reduction reactions (CO₂RRs) due to their unique properties. Rare earth metals, commonly referred to as “industrial vitamins”, have received attention in CO₂RR studies, particularly as rare earth single-atom catalysts. However, there is an urgent need for more systematic and in-depth research in this area, particularly concerning their stability, activity, and selectivity. In this study, the catalytic performance of lanthanide rare earth metals (REMs) anchored into Salen for the CO₂RR was comprehensively investigated using density functional theory (DFT). The analysis begins with a thorough examination of the stability of the REMs-Salen SACs and their CO₂ adsorption categories to assess the adsorption strength and initial activation of CO₂. Subsequently, the catalytic activity and selectivity of REM-Salen for CO₂RR-to-CO conversion were evaluated. The findings indicate that Yb-Salen exhibits the best performance in CO₂ reduction to CO, characterized by the lowest theoretical limiting potential of −0.56 V. Sm-Salen emerges as an excellent catalyst for producing syngas (CO and H₂) due to its comparable activity in both CO₂RR and the hydrogen evolution reaction (HER). Pm exhibits as an optimal candidate for the CO₂RR-to-CO reaction due to its highest CO₂RR-to-CO selectivity. These insights provide valuable guidance for the development of lanthanide rare earth-based SACs for CO₂RR applications.