A theoretical study of the electrochemical reduction of CO on cerium dioxide supported palladium single atoms and nanoparticles.

Pd/CeO catalysts show superior catalytic performance owing to their optimal cycling activity and stability. In this study, single-atom Pd and eight-atom Pd nanoparticle clusters were supported on the surface of CeO(110) to investigate the effect of loaded-metal size on the catalytic performance of the Pd-CeO system for CO reduction. We investigated the CO reduction reaction (CRR) that produces C products (CO, HCOOH, CHOH, and CH) on Pd/CeO and Pd/CeO by density functional theory. The structures, CO adsorption configurations, and CO reduction mechanisms of these two electrocatalysts were systematically studied. Subsequently, different reduction pathways on Pd/CeO and Pd/CeO were investigated to identify the optimal reaction pathway for further assessment. The results showed that both of these catalysts are more selective towards the production of CHOH than CH. Moreover, compared to Pd/CeO and Pd/CeO (from a previously reported study) the production of CHOH the CRR on Pd/CeO exhibited the lowest limiting potential. These results demonstrate the superiority of Pd/CeO as an electrocatalyst for the electrochemical reduction of CO to CHOH.