Article

Characterization of Oxygen Vacancy Associates within Hydrogenated TiO<sub>2</sub>: A Positron Annihilation Study

Xudong JiangSchool of Physics and Technology, Hubei Nuclear Solid Physics Key Laboratory and MOE Key Laboratory of Artificial Micro- and Nano-structures, Wuhan University, Wuhan 430072, ChinaYupeng ZhangSchool of Physics and Technology, Hubei Nuclear Solid Physics Key Laboratory and MOE Key Laboratory of Artificial Micro- and Nano-structures, Wuhan University, Wuhan 430072, ChinaJing JiangSchool of Physics and Technology, Hubei Nuclear Solid Physics Key Laboratory and MOE Key Laboratory of Artificial Micro- and Nano-structures, Wuhan University, Wuhan 430072, ChinaYongsen RongSchool of Physics and Technology, Hubei Nuclear Solid Physics Key Laboratory and MOE Key Laboratory of Artificial Micro- and Nano-structures, Wuhan University, Wuhan 430072, ChinaYancheng WangSchool of Physics and Technology, Hubei Nuclear Solid Physics Key Laboratory and MOE Key Laboratory of Artificial Micro- and Nano-structures, Wuhan University, Wuhan 430072, ChinaWU Yi-chuSchool of Physics and Technology, Hubei Nuclear Solid Physics Key Laboratory and MOE Key Laboratory of Artificial Micro- and Nano-structures, Wuhan University, Wuhan 430072, ChinaChunxu PanCenter for Electron Microscopy, Wuhan University, Wuhan 430072, China

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Abstract

This paper introduces a novel method for characterizing the oxygen vacancy associates in hydrogenation-modified TiO2 by using a positron annihilation lifetime spectroscopy (PALS). It was found that a huge number of small neutral Ti3+–oxygen vacancy associates, some larger size vacancy clusters, and a few voids of vacancy associates were introduced into hydrogenated TiO2. The defects blurred the atomic lattice high-resolution transmission electron microscopy (HRTEM) images and brought about the emergence of new Raman vibration. X-ray photoelectron spectroscopy (XPS) measurement indicated that the concentration of oxygen vacancies was 3% in the TiO2 lattice. The photoluminescence (PL) spectroscopy, photocurrent, and degradation of methylene blue indicated that the oxygen vacancy associates introduced by hydrogenation retarded the charge recombination and therefore improved the photocatalytic activity remarkably.

Identifiers

DOI: 10.1021/jp307573c

Citations and references

Cited by 20 references

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