A rational design of Ni_{: X}Co_yP@C cocatalyst for enhanced overall water splitting based on g-C₃N₄photocatalyst-the synergy of carbon-shell modification and bimetal modulation

Developing high-performance and low-cost cocatalysts is crucial to realize large-scale H2 production using solar energy. Herein, non-precious NixCoy-P@C core-shell nanoparticles (NPs) are synthesized as a high-active cocatalyst for photocatalytic water splitting. After coupling with g-C3N4, H2 and O2 production achieved 485 and 240 μmol g-1 h-1; the half-reaction of H2 evolution achieved 4182 μmol g-1 h-1, comparable to 4552 μmol g-1 h-1 of Pt/g-C3N4. The carbon shell leads to the controlled core size of NixCoy-P NPs, leading to an interfacial contact with g-C3N4, rapid electron transfer efficiency, and enhanced electron receiving capability of the catalyst. The carbon-shell and NixCoy-P NPs contribute to a significant synergy in promoting carrier separation and transfer efficiency. The Ni/Co ratio modulation in NixCoy-P NPs could optimize the work function of the cocatalyst for H2 evolution. Besides, carbon-shell introduces more pore structures and increases the surface area of the catalysts, which could provide more sites to receive electrons for H2 evolution. This work demonstrates the great potential of using high active and inexpensive NixCoy-P@C to replace expensive Pt for photocatalytic H2 evolution and open new avenues for optimizing cocatalyst with an excellent performance by bimetals modulation and carbon-shell coating.