Block polymer-modified molybdenum phosphide based on carbon nitride nanosheets for efficient hydrogen evolution

The development of nonprecious metals and green hydrogen evolution reaction (HER) electrocatalysts is a major research focus in the context of a two-carbon strategy. In this study, we synthesized a high-efficiency molybdenum phosphide (MoP) catalyst anchored to a porous nitrogen-doped carbon layer (MoP@NC-C₃N₄) via self-assembly and in situ phosphating processes with a clean phosphorus source (ammonium polyphosphate) and a pore-forming agent (F-108). The electrochemical test results demonstrate that the synthesized MoP@NC-C₃N₄ catalyst exhibits outstanding catalytic activity and durability in acidic and alkaline environments with overpotentials of 131 and 127 mV and Tafel slopes of 67 and 89 mV·dec⁻¹ (10 mA·cm⁻²), respectively. In the catalyst system, g-C₃N₄ provides both C and N atoms. In addition, the amorphous carbon and MoP nanoparticles exhibit a synergistic effect to promote charge transfer, thereby enhancing catalytic activity. The overpotential of MoP@NC-C₃N₄ in KOH electrolytes is lower than that of commercial Pt/C at current densities greater than 110 mA·cm⁻². This performance provides a valuable reference for potential industrial applications. The density functional theory results indicate that the Mo atom of MoP has the lowest hydrogen adsorption free energy and serves as the optimal catalytic active site for MoP@NC-C₃N₄. This study paves the way for the design and development of efficient HER electrocatalysts based on graphitic carbon nitrides (g-C₃N₄).