Surface plasmon-driven photoelectrochemical water splitting of a Ag/TiO2 nanoplate photoanode.

Abstract

A silver/titanium dioxide nanoplate (Ag/TiO2 NP) photoelectrode was designed and fabricated from vertically aligned TiO2 nanoplates (NP) decorated with silver nanoparticles (NPs) through a simple hydrothermal synthesis and electrodeposition route. The electrodeposition times of Ag NPs on the TiO2 NP were crucial for surface plasmon-driven photoelectrochemical (PEC) water splitting performance. The Ag/TiO2 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 TiO2 NP. It was clear that the enhanced light absorption properties and PEC performance for Ag/TiO2 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/TiO2 NP photoanode was attributed to the synergistic effects of the plasmonic Ag NPs and the TiO2 nanoplate. Interestingly, the plasmonic effect of Ag NPs not only increased the visible-light response (λmax = 570 nm) of TiO2 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 TiO2 hybrid nanostructure with a plasmonic enhancement for PEC water splitting.