Enhanced solar water splitting using plasmon-induced resonance energy transfer and unidirectional charge carrier transport

Solar water splitting by photoelectrochemical (PEC) reactions is promising for hydrogen production. The gold nanoparticles (AuNPs) are often applied to promote the visible response of wideband photocatalysts. However, in a typical TiO₂/AuNPs structure, the opposite transfer direction of excited electrons between AuNPs and TiO₂ under visible light and UV light severely limits the solar PEC performance. Here we present a unique Pt/TiO₂/Cu₂O/NiO/AuNPs photocathode, in which the NiO hole transport layer (HTL) is inserted between AuNPs and Cu₂O to achieve unidirectional transport of charge carriers and prominent plasmon-induced resonance energy transfer (PIRET) between AuNPs and Cu₂O. The measured applied bias photon-to-current efficiency and the hydrogen production rate under AM 1.5G illumination can reach 1.5% and 16.4 μmol·cm^-2·h^-1, respectively. This work is original in using the NiO film as the PIRET spacer and provides a promising photoelectrode for energy-efficient solar water splitting.