Copper phosphide decorated g-C3N4 catalysts for highly efficient photocatalytic H2 evolution

Designing functional heterojunctions to enhance photocatalytic hydrogen evolution is still a key challenge in the field of efficient solar energy utilization. Copper phosphides become an ideal material to serve as the cocatalysts during photocatalytic hydrogen evolution by virtue of the lower prices. In this study, we synthesized graphitic carbon nitride (g-C 3 N 4 ) based catalysts loaded with copper phosphide (Cu 3 P, Cu 97 P 3 ), which exhibit superior performance in photocatalytic H 2 evolution. Ultraviolet (UV)-visible spectroscopy illustrated that the absorption of light strengthened after the loading of copper phosphide, and the time-resolved transient photoluminescence (PL) spectra showed that the separation and transfer of the photoexcited carriers greatly improved. Moreover, both copper phosphide/g-C 3 N 4 photocatalysts exhibited a relatively high H 2 evolution rate: Cu 3 P/g-C 3 N 4 (maximum 343 μmol h −1  g −1 ), Cu 97 P 3 /g-C 3 N 4 (162.9 μmol h −1  g −1 ) while copper phosphide themself exhibit no photocatalytic activity . Thus, the copper phosphides (Cu 3 P, Cu 97 P 3 ) work as a cocatalyst during photocatalytic H 2 evolution. The cycling experiments illustrated that both copper phosphide/g-C 3 N 4 photocatalysts perform excellent stability in the photocatalytic H 2 evolution. It is worth noting that while the NaH 2 PO 2 was heated in the tube furnace for phosphorization to obtain Cu 3 P, the excessive PH 3 could pass through the solution of CuSO 4 to obtain Cu 97 P 3 at the same time, which significantly improved the utilization of PH 3 and reduced the risk of toxicity. This work could provide new strategies to design photocatalysts decorated with copper phosphide for highly efficient visible-light-driven hydrogen evolution.