Black TiO2 synthesized via magnesiothermic reduction for enhanced photocatalytic activity
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Utilizing solar energy for hydrogen evolution is a great challenge for its insufficient visible-light power conversion. In this paper, we report a facile magnesiothermic reduction of commercial TiO2 nanoparticles under Ar atmosphere and at 550 °C followed by acid treatment to synthesize reduced black TiO2 powders, which possesses a unique crystalline core–amorphous shell structure composed of disordered surface and oxygen vacancies and shows significantly improved optical absorption in the visible region. The unique core–shell structure and high absorption enable the reduced black TiO2 powders to exhibit enhanced photocatalytic activity, including splitting of water in the presence of Pt as a cocatalyst and degradation of methyl blue (MB) under visible light irradiation. Photocatalytic evaluations indicate that the oxygen vacancies play key roles in the catalytic process. The maximum hydrogen production rates are 16.1 and 163 μmol h−1 g−1 under the full solar wavelength range of light and visible light, respectively. This facile and versatile method could be potentially used for large scale production of colored TiO2 with remarkable enhancement in the visible light absorption and solar-driven hydrogen production.
KeywordsBlack TiO2 Magnesiothermic reduction Photocatalysis Hydrogen production Degradation of MB Nanostructured catalyst Solar energy
The authors acknowledge proofreading and revision of this manuscript by Ms. Yuxin Li.
This study was funded by the Natural Science Foundation of Shaanxi Province (2014JM-5057) and Research Project Supported by Cooperative Innovational Center for Technical Textiles, Shaanxi Province (2015ZX─19).
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
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