Electrochemical Imaging of Photoanodic Water Oxidation Enhancements on TiO<sub>2</sub> Thin Films Modified by Subsurface Aluminum Nanodimers.

Zhou, Xuan; Gossage, Zachary T; Simpson, Burton H; Hui, Jingshu; Barton, Zachary J; Rodríguez-López, Joaquín · ACS Nano · 2016

basic_science · Level V

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Abstract

Detecting metal plasmonic enhancements on the activity of semiconducting photoanodes for water oxidation is often obscured by the inherent electroactivity and instability of the metal in electrolyte. Here, we show that thin TiO<sub>2</sub> photoanodes modified by subsurface Al nanodimers (AlNDs) display enhancements that are consistent with plasmon modes. We directly observed enhancements by mapping the oxygen evolution rates on TiO<sub>2</sub>/AlND patterns using scanning electrochemical microscopy (SECM) while exciting the surface plasmons of the nanodimers. This study highlights the importance of sample configuration for the in situ characterization of metal/photoanode interactions and suggests a route for Al-based plasmonics applied to photoelectrochemistry.