Surface plasmon-driven photoelectrochemical water splitting of a Ag/TiO 2 nanoplate photoanode.

A silver/titanium dioxide nanoplate (Ag/TiO 2 NP) photoelectrode was designed and fabricated from vertically aligned TiO 2 nanoplates (NP) decorated with silver nanoparticles (NPs) through a simple hydrothermal synthesis and electrodeposition route. The electrodeposition times of Ag NPs on the TiO 2 NP were crucial for surface plasmon-driven photoelectrochemical (PEC) water splitting performance. The Ag/TiO 2 NP at the optimal deposition time of 5 min with a Ag element content of 0.53 wt% demonstrated a remarkably high photocurrent density of 0.35 mA cm -2 at 1.23 V vs. RHE under AM 1.5G illumination, which was 5 fold higher than that of the pristine TiO 2 NP. It was clear that the enhanced light absorption properties and PEC performance for Ag/TiO 2 NP could be effectively adjusted by simply controlling the loading amounts of metallic Ag NPs (average size of 10-30 nm) at different electrodeposition times. The superior PEC performance of the Ag/TiO 2 NP photoanode was attributed to the synergistic effects of the plasmonic Ag NPs and the TiO 2 nanoplate. Interestingly, the plasmonic effect of Ag NPs not only increased the visible-light response ( λ max = 570 nm) of TiO 2 but also provided hot electrons to promote photocurrent generation and suppress charge recombination. Importantly, this study offers a potentially efficient strategy for the design and fabrication of a new type of TiO 2 hybrid nanostructure with a plasmonic enhancement for PEC water splitting.