Enhanced Light-Driven Hydrogen Generation in Carbon Nitride Photocatalysts by Interfacial Electron-Transfer Cascade

Abstract This work aims at depositing high-crystallinity NiOx nanoparticles on the surface of graphitic carbon nitride (g-CN) nanosheets to improve light-driven hydrogen (H2) generation. Notably, assisted by transmission electron microscopy (TEM), we can discover that the solvothermal-processed NiOx nanoparticles attached over g-CN possess a great crystallinity with a diameter size of approx. 3-5 nm. As a result, the NiOx-nanoparticle loading can obviously enhance the H2 evolution rate (HER) of g-CN from 0 to 307 μmol h-1 g-1 under irradiation of AM1.5 spectra. Meanwhile, the apparent quantum efficiencies (AQE) at 400 nm can even approach the superior 1.5%. What’s more, X-ray photoelectron spectroscopy (XPS) and transient absorption (TA) spectra contribute to propose that the photogenerated electrons can first reduce Ni3+ into metallic nickel (Ni0), and then the H+ prefers to be reduced on the surface of Ni2+/Ni0 sites.