Dual Electronic and Interfacial Microenvironment Modulation on Rare-Earth Doped Ternary Pt Alloys Toward Alkaline Hydrogen Oxidation

Abstract

Alkaline hydrogen oxidation reaction (HOR) is the bottleneck restricting the performance of anion-exchange membrane fuel cells (AEMFCs), originating from sluggish Volmer kinetics induced by mismatched adsorption of H* and OH intermediates on commercial Pt/C catalysts, accompanied by high Pt cost, poor durability and inferior CO tolerance. Herein, Pr-doped PtMo ternary nanoparticles anchored on XC-72 carbon (PtMoPr/C) are fabricated via a facile wet chemical reduction strategy, where trace Pr dopant regulates electronic configuration and lattice strain of PtMo via unique 4f-5d orbital hybridization. Operando characterizations and DFT calculations verify that Pr induces downshifted Pt d-band center to weaken excessive Pt–H binding, provides abundant OH adsorption sites to accelerate Volmer step. Electronic modulation by Pr also increases the interfacial water and enhances the connectivity of hydrogen-bond networks within the electric double layers, synergistically boosting alkaline HOR performance. Electrochemical measurements demonstrate that the optimized PtMoPr/C delivers a mass activity of 2656.9 mA mgpt–1 at 50 mV vs RHE in 0.1 M KOH, 16-fold higher than that of benchmark Pt/C, together with outstanding anti-CO poisoning capability when exposed to CO-containing H2 feedstock. This work clarifies rare-earth Pr’s multifunctional effects and proposes an orbital modulation route to develop low-Pt HOR catalysts for practical AEMFC.