High-Entropy Alloys as Catalysts for the CO2 and CO Reduction Reactions: Experimental Realization

Conversion of carbon dioxide into selective hydrocarbon using a stable catalyst remains a holy grail in the catalysis community. The high overpotential, stability, and selectivity in the use of a single-metal-based catalyst still remain a challenge. In current work, instead of using pure noble metals (Ag, Au, and Pt) as the catalyst, a nanocrystalline high-entropy alloy (HEA: AuAgPtPdCu) has been used for the conversion of CO<inf>2</inf> into gaseous hydrocarbons. Utilizing an approach of multimetallic HEA, a faradic efficiency of about 100% toward gaseous products is obtained at a low applied potential (-0.3 V vs reversible hydrogen electrode). The reason behind the catalytic activity and selectivity of the high-entropy alloy (HEA) toward CO<inf>2</inf> electroreduction was established through first-principles-based density functional theory (DFT) by comparing it with the pristine Cu(111) surface. This is attributed to the reversal in adsorption trends for two out of the total eight intermediates - *OCH<inf>3</inf> and *O on Cu(111) and HEA surfaces.