Negatively Charged\nPt Atoms on Pd Nanocubes for an\nEnhanced Hydrogen Oxidation Performance in a Membrane Electrode Assembly

Proton-exchange membrane fuel cells (PEMFCs) constitute\nan advanced\nclean technology that efficiently transforms hydrogen energy into\nelectricity. However, the hydrogen oxidation reaction (HOR) at the\nanode heavily depends on precious metal catalysts, posing economic\nchallenges for PEMFCs commercialization. Consequently, developing\ncost-effective, high-activity HOR catalysts for anodes is imperative.\nIn this study, we developed a bimetallic Pd–Pt electrocatalyst\nfor acidic HOR, enhancing the catalytic activity by modulating the\nelectron transfer between the metals. X-ray photoelectron spectroscopy\nand X-ray absorption near-edge spectroscopy confirmed the presence\nof negatively charged Pt atoms. Electrochemical tests showed that\nPdPt<sub>0.1</sub> exhibited exceptional catalytic activity, with\nmass activities 3.2 and 11.5 times higher than those of commercial\nPt/C and Pd/C, respectively. Moreover, in membrane electrode assembly\ntests, PdPt<sub>0.1</sub> achieved a power density of 1.19 W cm<sup>–2</sup>, outperforming commercial Pt/C with a power density\nof 0.85 W cm<sup>–2</sup>. These remarkable performances are\nattributed to electron transfer between Pd and Pt, reducing the hydrogen\nbinding energy during HOR. This study offers valuable insights for\nthe controlled design of HOR catalysts based on the electron-transfer\ndirection.