Nickel phosphide cocatalyst and carbon defects simultaneously boosting the photocatalytic hydrogen production over carbon nitride

The suppression of photogenerated carrier recombination in carbon nitride and the consequent enhancement of its photocatalytic hydrogen evolution performance have emerged as a research hotspot in the field of photocatalysis. Herein, Nickel phosphide (Ni₂P) was anchored onto carbon nitride with carbon defects through a synthesis involving thermal polymerization and photoreduction. The existence of carbon defects derived from the rupture of carbon nitride (CN) heterocycles were beneficial to strengthening optical absorption and the separation capabilities of photogenerated carriers. Furthermore, Ni₂P cocatalysts could serve as electron acceptors that effectively accelerate the transfer and transport capabilities of the photogenerated charge carriers. Consequently, the 7 wt% Ni₂P/CNN photocatalyst achieved a maximum hydrogen evolution rate of 2062 μmol·g⁻¹·h⁻¹, which was 7.8 times and 6.2 times greater than that of Ni₂P/CN and Ni/CNN, respectively, and was comparable to the rate achieved by 3 wt% Pt/CNN. This result was comparable or even better than those reported previously. Our work provided a simply strategy for developing non-precious metal-based nickel phosphide photocatalysts for renewable solar-driven photocatalytic hydrogen production.