PlasmonicAu‐TiO 2 /ZnOCore–Shell Nanorod Array Photoanode for Visible‐Light‐Driven Photoelectrochemical Water Splitting

A plasmonic Au‐TiO 2 /ZnO core–shell nanorod array (NR) photoanode exhibits efficient photoelectrochemical water splitting induced by the plasmonic energy and type II TiO 2 /ZnO heterojunction. The plasmonic Au‐TiO 2 /ZnO core–shell NR photoanode provides a photocurrent density of 3.01 mA cm −2 at 1.7 V versus the reversible hydrogen electrode (RHE), almost 1.5 and 3 times higher than that of TiO 2 /ZnO core–shell NRs and TiO 2 NRs upon exposure into simulated solar light. Moreover, the plasmonic Au‐TiO 2 /ZnO core–shell NR photoanode shows a clear photocurrent density under visible‐light irradiation ( λ >400 nm) with a photocurrent density of 0.11 mA cm −2 at 1.23 V vs. RHE. The visible‐light‐excited photocurrent is mainly caused by the surface plasmon resonance effects produced by plasmonic Au nanoparticles, which benefit the visible‐light absorption and charge separation of the wide‐band‐gap TiO 2 /ZnO heterojunction through the electrons and resonant energy transfer. Additionally, the strong interfacial interaction between TiO 2 and ZnO leads to an effective photoinduced interfacial charge separation and transfer.