Electroless-deposited NiFeP catalyst-coated-membrane cathodes for anion exchange membrane water electrolysis

Abstract

The rational design of membrane electrode assemblies is crucial for anion exchange membrane (AEM) water electrolysis. In this study, a series of NiFeP catalyst-coated-membranes (CCMs) were synthesized using a Pd-catalyzed electroless deposition method, which served as a cathode for an AEM water electrolyzer. This electroless deposition method enables the in situ growth of NiFeP electrocatalysts on the AEM surface, thus mitigating the degradation of the ionomer/binder during long-term water electrolysis and decreasing the resistance of the membrane electrode assembly. The Ni_0.79Fe_0.08P_0.13 electrocatalyst delivered −500 mA cm⁻² at an overpotential of −0.47 V in 1.0 M K₂CO₃, exhibiting outstanding hydrogen evolution reaction (HER) performance. Furthermore, the Ni_0.79Fe_0.08P_0.13 electrocatalyst demonstrated excellent stability by maintaining −500 mA cm⁻² for over 100 h with only a 5.7% increase in overpotential. The exceptional HER catalytic performance of the Ni_0.79Fe_0.08P_0.13 electrocatalyst was attributed to the optimized electronic structure resulting from Fe incorporation and the formation of amorphous regions, which enhanced the catalytic performance and facilitated hydrogen diffusion. This work offers new insights into the fabrication and analysis of ionomer/binder-free CCMs for improving the performance of AEM water electrolysis devices.