A rational design of NixCoyP@C cocatalyst for enhanced overall water splitting based on g-C3N4 photocatalyst — the synergy of carbon-shell modification and bimetal modulation

Abstract

Developing high-performance and low-cost cocatalysts is crucial to realize large-scale H₂ production using solar energy. Herein, non-precious Ni_xCo_y–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 Ni_xCo_y–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 Ni_xCo_y–P NPs contribute to a significant synergy in promoting carrier separation and transfer efficiency. The Ni/Co ratio modulation in Ni_xCo_y–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 Ni_xCo_y–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.