Modification of 1D TiO2 nanowires with GaOxNy by atomic layer deposition for TiO2@GaOxNy core-shell nanowires with enhanced photoelectrochemical performance

Jia-Jia Tao, Hong-Ping Ma, Kai-Ping Yuan, Yang Gu, Jian-Wei Lian, Xiao-Xi Li, Wei Huang, Michael Nolan, Hong-Liang Lu, David-Wei Zhang

Research output: Contribution to journalArticle

Abstract

As a well-known semiconductor that can catalyse the oxygen evolution reaction, TiO 2 has been extensively investigated for its solar photoelectrochemical water properties. Unmodified TiO 2 shows some issues, particularly with respect to its photoelectrochemical performance. In this paper, we present a strategy for the controlled deposition of controlled amounts of GaO xN y cocatalysts on TiO 2 1D nanowires (TiO 2@GaO xN y core-shell) using atomic layer deposition. We show that this modification significantly enhances the photoelectrochemical performance compared to pure TiO 2 NW photoanodes. For our most active TiO 2@GaO xN y core-shell nanowires with a GaO xN y thickness of 20 nm, a photocurrent density up to 1.10 mA cm -2 (at 1.23 V vs. RHE) under AM 1.5 G irradiation (100 mW cm -2) has been achieved, which is 14 times higher than that of unmodified TiO 2 NWs. Furthermore, the band gap matching with TiO 2 enhances the absorption of visible light over unmodified TiO 2 and the facile oxygen vacancy formation after the deposition of GaO xN y also provides active sites for water activation. Density functional theory studies of model systems of GaO xN y-modified TiO 2 confirm the band gap reduction, high reducibility and ability to activate water. The highly efficient and stable systems of TiO 2@GaO xN y core-shell nanowires with ALD deposited GaO xN y demonstrate a good strategy for the fabrication of core-shell structures that enhance the photoelectrochemical performance of readily available photoanodes.

Original languageEnglish
Pages (from-to)7159-7173
Number of pages15
JournalNanoscale
Volume12
Issue number13
DOIs
Publication statusPublished - 24 Feb 2020

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