Enhanced Photoelectrochemical Response and Stability of ZnO/C₃N₄ Electrode through In Situ Growth of the C₃N₄ Layer on Electrodeposited ZnO Electrode

A composite was formed to improve the photo-generated carrier separation rate of semiconductor oxides synthesized by in situ electrodeposition and calcination. ZnO/g-C 3 N 4 was deposited on the surface of Au/FTO through simultaneous adsorbing during electrodeposition and calcination. Characterization showed the g-C 3 N 4 layer was an ultrathin protective film above the surface of ZnO. The composite Au/ZnO/g-C 3 N 4 had a photocurrent up to 0.24 mA cm −2 at 1.23 V vs RHE, 70% higher than bare ZnO. In this structure, the holes of ZnO generated by lights can transfer to the g-C 3 N 4 layer and electrons can transfer to the gold layer, accelerating charge transfer and reducing the accumulation of holes on the surface of ZnO, enhancing the photoresponse and stability. The separation of holes by g-C 3 N 4 is a critical part of this structure.