Suppressing the aggregation and optimizing the electronic structure of porous Ni nanosheets by POMs-derived Mo2N for efficient hydrogen evolution in AEM water electrolysis
NiMo-based catalysts are promising for the hydrogen evolution reaction (HER), yet optimizing their electronic structure and enhancing mass transfer remain challenging. Here, we report a route to synthesize two-dimensional (2D) porous Mo2N-Ni heterojunction nanosheets with tuned Ni/Mo ratio for enhanced alkaline HER. The precursor is assembled from polyoxometalate clusters (PMo12) and layered Ni(OH)2. The interaction between PMo12 and Ni(OH)2 suppresses particle agglomeration during pyrolysis, yielding 2D porous sheets composed of small Mo2N-Ni units. Electron transfer from Ni to Mo2N redistributes electrons at the heterojunction, optimizing intermediate adsorption/desorption. The porous structure enhances mass transfer, reducing catalyst impedance. The optimized catalyst exhibits an overpotential of 19 mV at 10 mA cm−2, comparable to commercial Pt/C. An anion exchange membrane (AEM) electrolyzer pairing this catalyst with NiFe-LDH achieves 500 mA cm−2 at 1.80 V and operates stably for 300 h. This assembly method offers a scalable strategy for efficient catalyst production.