Disorder engineering of undoped TiO2 nanotube arrays for highly efficient solar-driven oxygen evolution

M. Salari; S. H. Aboutalebi; A. Aghassi; P. Wagner; A. J. Mozer; G. G. Wallace

doi:10.1039/C4CP03177F

Disorder engineering of undoped TiO₂ nanotube arrays for highly efficient solar-driven oxygen evolution†

M. Salari,*^a S. H. Aboutalebi,^b A. Aghassi,^a P. Wagner,^a A. J. Mozer^a and G. G. Wallace*^a

* Corresponding authors

^a ARC Centre of Excellence for Electromaterials Science, Intelligent Polymer Research Institute, University of Wollongong, Wollongong, NSW, Australia
E-mail: ms591@uowmail.edu.au, gwallace@uow.edu.au

^b Institute for Superconducting and Electronic Materials, ARC Centre for Electromaterials Science, University of Wollongong, Wollongong, NSW, Australia

Abstract

The trade-off between performance and complexity of the device manufacturing process should be balanced to enable the economic harvest of solar energy. Here, we demonstrate a conceptual, yet practical and well-regulated strategy to achieve efficient solar photocatalytic activity in TiO₂ through controlled phase transformation and disorder engineering in the surface layers of TiO₂ nanotubes. This approach enabled us to fine-tune the bandgap structure of undoped TiO₂ according to our needs while simultaneously obtaining robust separation of photo-excited charge carriers. Introduction of specific surface defects also assisted in utilization of the visible part of sunlight to split water molecules for the production of oxygen. The strategy proposed here can serve as a guideline to overcome the practical limitation in the realization of efficient, non-toxic, chemically stable photoelectrochemical systems with high catalytic activity at neutral pH under visible illumination conditions. We also successfully incorporated TiO₂ nanotube arrays (TNTAs) with free-based porphyrin affording a pathway with an overall 140% enhanced efficiency, an oxygen evolution rate of 436 μL h⁻¹ and faradic efficiencies over 100%.

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Article information

DOI: https://doi.org/10.1039/C4CP03177F
Article type: Paper
Submitted: 18 Jul 2014
Accepted: 12 Jan 2015
First published: 15 Jan 2015

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Phys. Chem. Chem. Phys., 2015,17, 5642-5649

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Disorder engineering of undoped TiO₂ nanotube arrays for highly efficient solar-driven oxygen evolution

M. Salari, S. H. Aboutalebi, A. Aghassi, P. Wagner, A. J. Mozer and G. G. Wallace, Phys. Chem. Chem. Phys., 2015, 17, 5642 DOI: 10.1039/C4CP03177F

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