Mass-efficient catalyst layer of hierarchical sub-nanosheets on nanowire for practical proton exchange membrane electrolyzer

Proton exchange membrane water electrolysis (PEMWE) is promising for the sustainable and scalable production of green hydrogen, yet it is now technologically limited by the high loading of precious Ir in the anodic catalyst layer (CL). Herein, we report a kind of anodic CL composed of hierarchical IrRu sub-nanosheets on nanowires for boosting the operational efficiency of PEM electrolyzers. Integrating this hierarchical CL into PEMWE with a low Ir loading of 0.35 mgIr cm−2, we demonstrated an outstanding water electrolysis performance—a hydrogen production current density of 1.0 A cm−2 at 1.65 V, along with a high overload current density of 6.0 A cm−2. In particular, the PEMWE could operate stably at 2.0 A cm−2 for more than 240 h. We further demonstrated the application of our designed PEMWE in a commercial hydrogen generator with a high H2 generation rate of ∼300 mL min−1.