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

The development of non-precious metals and green hydrogen evolution electrocatalysts in the context of a two-carbon strategy has been a topic of intense research. In this paper, we prepared a high-efficiency MoP catalyst anchored to porous nitrogen-doped carbon layer (MoP@NC-C3N4) via self-assembly and in-situ phosphating processes with a clean phosphorus source (ammonium polyphosphate, APP) and (pore former, F-108). The results of electrochemical tests show that MoP@NC-C3N4 displays outstanding catalytic activity and endurance 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. Herein, g-C3N4 provides both C and N atoms, and in addition, the amorphous carbon and MoP nanoparticles have a synergistic effect to promote the progress charge transfer and thus increase the catalytic activity. More importantly, the overpotential of MoP@NC-C3N4 in KOH solution is lower than the commercial Pt/C at current densities greater than 110 mA cm-2, which provides a certain reference value for industrial production. DFT results indicate that the Mo atom of MoP has the lowest hydrogen adsorption free energy and is the best active site for MoP@NC-C3N4. This study illuminates the way for the fabrication and research of efficient HER electrocatalysts on account of g-C3N4.