Solution Plasma Process-Derived Defect-Induced Heterophase Anatase/Brookite TiO2 Nanocrystals for Enhanced Gaseous Photocatalytic Performance

Sudhagar Pitchaimuthu; Kaede Honda; Shoki Suzuki; Akane Naito; Norihiro Suzuki; Ken-Ichi Katsumata; Kazuya Nakata; Naoya Ishida; Naoto Kitamura; Yasushi Idemoto; Takeshi Kondo; Makoto Yuasa; Osamu Takai; Tomonaga Ueno; Nagahiro Saito; Akira Fujishima; Chiaki Terashima

doi:10.1021/acsomega.7b01698

Solution Plasma Process-Derived Defect-Induced Heterophase Anatase/Brookite TiO₂ Nanocrystals for Enhanced Gaseous Photocatalytic Performance

ACS Omega. 2018 Jan 24;3(1):898-905. doi: 10.1021/acsomega.7b01698. eCollection 2018 Jan 31.

Authors

Sudhagar Pitchaimuthu^{1

2}, Kaede Honda¹, Shoki Suzuki¹, Akane Naito¹, Norihiro Suzuki¹, Ken-Ichi Katsumata¹, Kazuya Nakata^{1

1}, Naoya Ishida^{1

1}, Naoto Kitamura^{1

1}, Yasushi Idemoto^{1

1}, Takeshi Kondo^{1

1}, Makoto Yuasa^{1

1}, Osamu Takai³, Tomonaga Ueno⁴, Nagahiro Saito⁴, Akira Fujishima¹, Chiaki Terashima¹

Affiliations

¹ Photocatalysis International Research Center, Research Institute for Science & Technology, and Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan.
² Multi-functional Photocatalyst and Coatings Group, SPECIFIC, College of Engineering, Swansea University (Bay Campus), Swansea SA1 8EN, Wales, U.K.
³ Materials and Surface Engineering Research Institute, Kanto Gakuin University, 1162-2 Ogikubo, Odawara, Kanagawa 250-0042, Japan.
⁴ Department of Materials, Physics and Energy Engineering, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan.

Abstract

We report a simple room-temperature synthesis route for increasing the reactivity of a TiO₂ photocatalyst using a solution plasma process (SPP). Hydrogen radicals generated from the SPP chamber interact with the TiO₂ photocatalyst feedstock, transforming its crystalline phase and introducing oxygen vacancy defects. In this work, we examined a pure anatase TiO₂ as a model feedstock because of its photocatalytic attributes and well-characterized properties. After the SPP treatment, the pure anatase crystalline phase was transformed to an anatase/brookite heterocrystalline phase with oxygen vacancies. Furthermore, the SPP treatment promoted the absorption of both UV and visible light by TiO₂. As a result, TiO₂ treated by the SPP for 3 h showed a high gaseous photocatalytic performance (91.1%) for acetaldehyde degradation to CO₂ compared with the activity of untreated TiO₂ (51%). The SPP-treated TiO₂ was also more active than nitrogen-doped TiO₂ driven by visible light (66%). The overall photocatalytic performance was related to the SPP treatment time. The SPP technique could be used to enhance the activity of readily available feedstocks with a short processing time. These results demonstrate the potential of this method for modifying narrow-band gap metal oxides, metal sulfides, and polymer composite-based catalyst materials. The modifications of these materials are not limited to photocatalysts and could be used in a wide range of energy and environment-based applications.