Ag@Pd bimetallic structures for enhanced electrocatalytic CO 2 conversion to CO: an interplay between the strain effect and ligand effect.

Electrochemical CO 2 reduction reactions provide a promising path to effectively convert CO 2 into valuable chemicals and fuels for industries. Among the many CO 2 conversion catalysts, Pd stands out as a promising catalyst for effective CO 2 to CO conversion. Here, using the misfit strain strategy, Ag@Pd bimetallic nanoparticles with different Pd overlayer contents were prepared as CO 2 reduction catalysts. By varying the Pd overlayer content, all the Ag@Pd bimetallic nanoparticles exhibited superior CO 2 conversion performance over their Pd and Ag nanoparticle counterparts. An optimal Pd-to-Ag ratio of 1.5 : 1 yielded the highest CO faradaic efficiency of 94.3% at -0.65 V vs. RHE with a high CO specific current density of 3.9 mA cm -2 . It was found that the Pd content can substantially affect the interplay between the strain effect and ligand effect, resulting in optimized binding properties of the reaction intermediates on the catalyst surface, thereby enhancing the CO 2 reduction performance.