PtFeCoNiMoYZr/YZrO heterojunction catalysis for anion exchange membrane water electrolyzers

Abstract

Heterojunction catalysts play an important role among emerging catalytic systems, as they can significantly optimize the surface adsorption energy of active sites and enhance catalytic activity. In this study, a Pt-based high-entropy alloy/binary oxide heterojunction catalyst is designed and synthesized. The catalytic mechanisms are systematically investigated and the results reveal that the heterojunction structure and binary oxide component synergistically modulate the d-band center, electron transfer, and oxygen vacancy defects within the catalyst, thereby achieving enhanced bifunctional catalytic performance and facilitating efficient operation of an anion exchange membrane water electrolyzer (AEMWE). The synthesized PtFeCoNiMoYZr/YZrO heterojunction catalyst exhibits low overpotentials of merely 22 and 73 mV for the hydrogen evolution reaction (HER) at current densities of 10 and 100 mA cm⁻², respectively. Remarkably, it maintains 92.1% of its initial activity after 215 hours of continuous operation at 10 mA cm⁻². For the oxygen evolution reaction (OER), the catalyst shows an overpotential of 254 mV at 10 mA cm⁻². When applied in an AEMWE operating with an alkaline electrolyte, the catalyst delivers a high current density of 1.0 A cm⁻² at 2.4 V, maintaining excellent stability over 145 hours. This work offers valuable insights into the development of high-performance high-entropy alloy/oxide heterojunction catalysts.