Scalable and inexpensive strategy to fabricate CuO/ZnO nanowire heterojunction for efficient photoinduced water splitting

In this paper, highly efficient and stable CuO/ZnO nanowire (CuO/ZnO-nw) based photocathode was fabricated using a facile and scalable technique for application in photoelectrochemical water splitting. Electro-deposition of Cu film on FTO glass followed by a subsequent chemical oxidation and dip-coating methods was implemented to fabricate a p-type CuO/ZnO-nw heterostructure photoelectrode. The as-prepared CuO/ZnO-nw heterostructure consisted of a copper (II) oxide (CuO) nanowire covered by zinc oxide (ZnO) nanoparticle film serving as both protecting and charge transfer layer. We optimized the coating concentration and the number of layers to achieve enhanced p-type CuO/ZnO-nw photoelectrode material. The best photocathode material exhibited a maximum current of − 8.1 mAcm−2 at 0 versus RHE. The obtained photocurrent density was outstanding compared to other reported CuO-based heterostructure photoelectrodes. The enhancement in photocurrent performance originated from the combined effect of charge separation and the light absorption properties of the heterostructure photoelectrode. The result demonstrated a simple and scalable approach for the fabrication of enhanced CuO nanowire-based photoelectrode for the production of H2 using solar light.