Synergistic enhancement of surface-doped Mn and Cu-mediated hierarchical reconstruction in Co–Ni–Cu–Mn electrocatalyst for hydrogen production in proton exchange membrane water electrolyzer

Multicomponent electrocatalysts offer inherent advantages because of the synergistic effects among their constituents at the atomic scale, rendering them suitable for enhancing the catalytic activity of the hydrogen evolution reaction (HER). In this study, self-supported Co–Ni–Cu–Mn electrocatalysts are deposited on porous carbon paper via one-step electrodeposition. These electrocatalysts exhibit remarkable synergistic enhancements, resulting in both improved acidic HER activity and overall durability. This synergy arises from the development of hierarchical structures triggered by Cu and Mn-doped surface. During HER, Cu leaches from the catalyst surface, while simultaneously, surface -doped Mn synergistically prevents activity degradation and facilitates surface reconstruction. The combination of these interactions helps to achieve a low overpotential of 100 mV at 10 mA cm ⁻² . The Co–Ni–Cu–Mn electrocatalyst is applied as a high-efficient cathode gas diffusion electrode for proton exchange membrane water electrolyzer (PEMWE). The PEMWE single-cell equipped with Pt-free cathode achieves an outstanding performance of 2.57 A cm ⁻² at 2.0 V _cell , with exceptional stability for 60 h under high current density of 2.0 A cm ⁻² . The successful implementation of the quaternary electrocatalyst highlights its potential for tailoring catalytic properties for hydrogen production, effectively bridging the gap between fundamental understanding and practical realization for cost-efficient PEMWE.