Medium‐Entropy Amorphous Alloyed Single‐Atom Pd Catalysts for Direct Ethylene Glycol Fuel Cells

Abstract

ABSTRACT Precise regulation of the d‐band center of palladium (Pd) for targeted electrocatalysis held tremendous scientific and technological potential, yet achieving this via rational structural design remained challenging. Herein, we present medium‐entropy amorphous alloyed single‐atom (MEAASA) Pd nanosheets (NSs), wherein the d‐band center of Pd was delicately modulated to an optimal value via the synergistic effect of medium‐entropy alloying, single‐atom coordination, and oxyphilic Cr/Mo/W modification. The as‐synthesized PdCrMoW MEAASA NSs exhibited exceptional mass activities of 2.15 and 15.19 A mg − 1 for the oxygen reduction reaction (ORR) and ethylene glycol oxidation reaction (EGOR), respectively, which were 15.4 and 4.4 times higher than those of commercial Pt/C. Experimental results suggested that the optimized d‐band center not only balanced the adsorption and activation of key intermediates but also suppressed CO formation via a non‐CO dominated pathway, enabling a 4 e − ORR process and a nearly complete 10 e − EGOR process with 91.5% C1 selectivity. In practical direct ethylene glycol fuel cells (DEGFCs), the PdCrMoW MEAASA NSs delivered a peak power density of 117 mW·cm − 2 , markedly outperforming the state‐of‐the‐art commercial Pt/C catalyst.