Rational design of low loading Pd-alloyed Ag nanocorals for high current density CO2-to-CO electroreduction at elevated pressure

Abstract

Adjusting a bimetallic electrocatalyst's geometric and electronic structure to promote a certain reaction pathway and provide more active sites is a viable approach for improving the activity and selectivity of an electrocatalytic CO2 reduction process. Here, the authors, for the first-time design, self-supported 3D Ag–Pd nano-coral electrodes with a low loading Pd content through a simple and scalable approach using hydrogen bubble dynamic templates. At −0.6 V vs. Reversible hydrogen evaluation (RHE) CO2, the Ag96.1Pd3.9 bimetallic electrode converts CO2 to CO with a promoted faradic efficiency of 91.5% and partial current density (18.13 mA cm −2). This upgraded activity can be attributed to the aspects that the addition of Pd supports the vital intermediate generation with coral morphology, offers numerous active sites and rises CO2 concentration. In addition, because the catalyst is self-supported, there is no overpotential at the catalyst/support interface. Finally, CO achieved a partial current density of −318 mA cm−2 by rising CO2 pressure to as elevated as 9.5 bar to raise CO2 content. To the best of our knowledge, these findings establish a high record in neutral pH electrolytes for most Ag-based electrodes.