High-Density-Cluster Ru Catalyst Substitute for Pt/C Benchmark Improves Membrane Water Electrolysis

The hydrogen evolution reaction (HER) is of great importance for the renewable energy conversion to hydrogen fuel via water electrolysis. However, the current benchmark Pt/C catalyst suffers from high cost, pH sensitivity, and deficient durability, severely restricting the large-scale development of membrane water electrolysis. Herein, we develop a cost-effective Pt-free catalyst featuring high-density, ultrafine Ru nanoclusters modified with CoP and uniformly dispersed on nitrogen-doped carbon films (NCF). This catalyst achieves not only superior HER activity across a wide pH range but also robust stability at ampere-level large current densities, manifesting as a competitive alternative to commercial Pt/C. Typically, Ru-CoP/NCF exhibits an overpotential of only 22 mV at 10 mA cm^-2 in acidic media, with the mass activity and price activity 1.21 and 2.18 times higher than Pt/C, respectively. A proton exchange membrane water electrolyzer using Ru-CoP/NCF catalyst delivers a high current density of 1.0 A cm^-2 at a voltage of merely 1.67 V and sustains long-term operation for 780 h with a minimal decay rate of 84 µV h^-1. This Ru-CoP/NCF catalyst thus demonstrates practical potential for the development of non-Pt membrane electrodes.