(41g) Expanding Single-Atom Alloy Concept to Electrocatalysis: PGM Unexpectedly Facilitates Copper for Hydrocarbon Formations through CO2 Reduction

Metal alloying approach is being widely used to improve the electrochemical CO₂ reduction reaction (CO₂RR) for copper-based catalysts. Incorporating platinum group metals (PGM) is known to be effective in thermal catalysis for facile activation of H* radicals and hence promotes hydrogenation steps for HCs production. However, for electrocatalytic hydrogenation reactions in aqueous phase including CO₂RR, PGMs are rarely used because these metals riskily promote the competitive hydrogen evolution reaction (HER). Herein, we report PGM species can be incorporated into copper nanoparticles to form Pd₁Cu and Pt₁Cu single atom alloy (SAA) catalysts to deliver over ten times higher hydrogenation production rates (CH₄ and C₂H₄) than its parent Cu-only counterpart, while the intrinsic HER inclination of the PGM is suppressed. Notably, these benefits won’t be realized by using similarly formulated dilute-alloy catalysts with PGMs in the form of small clusters, where we found the side effects of PGMs in triggering HER and *CO intermediate poisoning would prevail. Intriguingly, the presence of single-atom PGM enables the facile generation of the very similar reaction intermediates at lower overpotentials, such as *COOH, *CHO, *OCH₂, and *COCHO that would otherwise be observed on Cu-only catalysts but at higher voltages. The high likelihood of the intact hydrogenation pathway after incorporating the single-atom PGM on copper was further confirmed by adopting copper-shape-controlled SAAs, namely cube-Pd₁Cu and octahedron-Pd₁Cu. We found that, with or without the PGM activity boosts, the Cu(111)-based catalysts will consistently favor CH₄ formation while the Cu(100)-based catalysts will favor C₂H₄ formation. In summary, we proved that the SAA strategy, by incorporating the high-risk PGMs to various copper hosts, can now be extended to CO₂RR to boost the reaction without jeopardizing the selectivity of the host metal or bringing in side reactions.