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

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 Ag_96.1Pd_3.9 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.