Bifunctional Cu₃P Decorated g-C₃N₄ Nanosheets as a Highly Active and Robust Visible-Light Photocatalyst for H₂ Production

Abstract

The rational design of sustainable noble-metal-free heterojunctions remains a key challenge for highly efficient and durable photocatalytic H2 production. In this study, it was revealed that the robust copper phosphide (Cu3P) nanoparticles may serve as a cocatalyst and a p-type semiconductor at low (1.5 wt %) and high (10 wt %) loading contents, respectively. Both Cu3P cocatalyst and semiconductor could evidently boost visible-light-driven photocatalytic H2 production over graphitic carbon nitride (g-C3N4) nanosheets. Comparably speaking, the heterojunction effects between p-type Cu3P and n-type g-C3N4 are speculated to play a more prominent role in dramatically boosting photocatalytic H2 production than the electron-sink roles of surface Cu3P cocatalysts. Impressively, among all the as-fabricated photocatalysts, high quality 10 wt % g-C3N4–Cu3P could achieve the highest photocatalytic H2-production rate of 159.41 μmol g–1 h–1, which is approximately 1014 times higher than that of pristine g-C3N4. In cycling experiments, g-C3N4–10 wt % Cu3P exhibited an acceptable photostability. More importantly, it was further demonstrated that earth-abundant dual-functional Cu3P nanoparticles could markedly facilitate the separation of electron–hole pairs and H2-evolution kinetics, thus achieving distinctly boosted photocatalytic H2 generation. This work will provide new insights into the rational design of environmentally friendly g-C3N4-based hybrid nanoheterojunctions for visible-light-responsive photocatalytic H2 generation through loading noble-metal-free bifunctional cocatalysts on semiconductors.