Dynamic template reconstruction induced mesoporous iridium catalysts for high-current-density PEMWE

Enhancing current density is a crucial strategy for reducing costs and improving the efficiency of green hydrogen production through water electrolysis. However, mass diffusion and proton transport limitations under high-current densities remain serious obstacles. Here, we proposed a novel strategy to construct a three-dimensional mesoporous skeleton structure of IrO₂ to address the limitations. By utilizing the dynamic loading of Ir nanoparticles during the La₂O₃ template reconstruction process, high-density embedding of ultra-small Ir nanoparticles in the template is achieved. During the electrochemical process, in situ oxidation of Ir nanoparticles combined with template leaching results in the formation of a three-dimensional, mesoporous IrO₂ structure. The developed catalyst enables proton exchange membrane water electrolysis (PEMWE) to achieve stable operation for over 2,700 h at a current density of 5 A cm⁻² with a voltage degradation rate of ∼0.38 μV h⁻¹, which meets the 2030 EU Clean Hydrogen JU target and 2026 US Department of Energy (DOE) target.