High-Entropy Alloys as Catalysts for the CO<sub>2</sub> and CO Reduction Reactions: Experimental Realization
Subramanian Nellaiappan, Nirmal Kumar Katiyar, Ritesh Kumar, Arko Parui, Kirtiman Deo Malviya, K.G. Pradeep, Abhishek K. Singh, Sudhanshu Sharma, Chandra Sekhar Tiwary, Krishanu Biswas
Abstract
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 CO2 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 CO2 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 - *OCH3 and *O on Cu(111) and HEA surfaces.