Hydrogen-induced p-d orbital hybridization and tensile strain of PdGa single-atom alloy metallene boosts complete electrooxidation of ethanol

Abstract

Ethanol oxidation reaction (EOR) at the anode of direct ethanol fuel cells (DEFCs) obeys C1/C2 dual-pathway reaction mechanism, and improving the selectivity of C1 pathway is crucial to the commercialization of DEFCs. Herein, a novel hydrogen-implanted PdGa single-atom alloy metallene (H-Ga1Pdene) is designed for optimizing the C1 pathway to achieve greatly enhanced C1 pathway selectivity through electronic and strain engineering. Benefiting from the strong p-d orbital hybridization interaction and tensile strain effect induced by hydrogen-implantation, H-Ga1Pdene exhibits high mass activity of 10.34 A mgPd−1 and C1 pathway selectivity of 54.7%, both showing an order of magnitude higher than that of commercial Pd/C. Theoretical calculations reveal that the p-d hybridization interaction could effectively accelerate the C-C bond cleavage and tensile strain enable efficient oxidation of CO* and CH3 * produced by the C-C bond cleavage in C1 pathway, enabling H-Ga1Pdene to efficiently catalyze the complete electrooxidation of ethanol through the C1 pathway.