Steering the absorption configuration of intermediates over Pd-based electrocatalysts toward efficient and stable CO₂ reduction

Abstract

Palladium (Pd) catalysts are promising for electrochemical reduction of CO2 to CO but often can be deactivated by poisoning owing to the strong affinity of *CO on Pd sites. Theoretical investigations reveal that different configurations of *CO endow specific adsorption energies, thereby dictating the final performances. Here, a regulatory strategy toward *CO absorption configurations is proposed to alleviate CO poisoning by simultaneously incorporating Cu and Zn atoms into ultrathin Pd nanosheets (NSs). As-prepared PdCuZn NSs can catalyze CO production at a wide potential window (−0.28 to −0.78 V vs RHE) and achieve a maximum FECO of 96% at −0.35 V. Impressively, it exhibits stable CO production of 100 h under ∼95% FECO with no decay. Combined results from X-ray analysis, in situ spectroscopy, and theoretical simulations suggest that the codoping strategy not only optimizes the electronic structure of Pd but also weakens the binding strengths of *CO and increases the proportion of weak-binding linear *CO absorption configuration on catalysts’ surfaces. Such targeted adoption of weakly bound configurations abates the energy barrier of *CO desorption and facilitates CO production. This work confers a useful design tactic toward Pd-based electrocatalysts, codoping for steering adsorption configuration to achieve highly selective and stable CO2-to-CO conversion.