Plasmonic Ag nanoparticles and p-type CuO-modified ZnO nanorods for efficient photoelectrochemical water splitting

The light absorption range of semiconductor materials and the separation rate of electron–hole pairs are significant challenge in photoelectrochemical (PEC) water splitting. In this work, we first prepared a ternary heterojunction of ZnO/CuO/Ag by chemical bath deposition method. The formation of the heterojunction can improve the absorption range and increase the electron–hole pairs' separation rate, and the loading of plasmonic Ag nanoparticles can expand the absorption range of visible light and generate more photogenerated electrons through surface plasmon resonance (SPR). The ZnO/CuO/Ag heterojunction photoelectrode reveals an efficient photocurrent density of 3.45 mA cm⁻² at 1.23 V vs. RHE, which is 3.08 and 1.12 times higher compared with ZnO and ZnO/CuO photoelectrode, respectively. This study shows that the simultaneous reaction of heterojunction and plasmonic noble metal nanoparticles can synergistically improve the photoelectric properties of photoanodes in photoelectrochemical water-splitting system.