Structure-Dependent HER Activity and Durability on Flat and Macroporous Ni-P Electrocatalysts in Acidic Medium.

The development of sustainable non-noble-metal catalysts for producing high-purity hydrogen via water electrolysis as an alternative to the state-of-the-art Pt-based materials has attracted considerable interest in recent years. Nevertheless, the widespread adoption of these catalysts remains limited due to their insufficient stability, particularly in an acidic environment. In this study, both flat and macroporous Ni-P alloy catalysts with controlled compositions and microstructures were synthesized via electroless deposition. The results demonstrate that increasing the phosphorus content up to 12 wt %, applying heat treatments, and utilizing macroporous templates significantly enhance catalytic activity for hydrogen evolution reaction, approaching that of Pt/C catalysts. Nevertheless, a trade-off between the catalytic efficiency and corrosion resistance was observed. Advanced characterization techniques, including scanning Kelvin probe force microscopy, revealed that heat-treatment-induced structural modifications play a crucial role in the catalyst degradation mechanism and can provoke the formation of local galvanic couples under negative polarization. These results offer important insights into the structure-property relationships of Ni-P alloys, highlighting their potential as efficient and durable HER catalysts in acidic media.