課題番号                ：S-19-NI-0007

利用形態                ：機器利用

利用課題名（日本語）    ：可視光応答型光触媒セラミックスのTEM観察

Program Title (English) ：TEM observation of Visible-Light-Active Ceramic Photocatalysts

利用者名（日本語）      ：ラザヴィ　ハディ

Username (English)     ：Hadi Razavi

所属名（日本語）        ：名古屋工業大学　先進セラミックス研究所

Affiliation (English)  ：Advanced Ceramics Research Center, Nagoya Institute of Technology

１．概要（Summary ）

Over the past decades, the accumulation of organic pollutants in surface water, groundwater, and even drinking water have raised as a serious issue. A photocatalytic process using a semiconductor like TiO₂ is one solution for the degradation of organic pollutants in water, however, the low efficiency of the photocatalytic reaction is still a problem. In this study, hollow TiO₂ particles with different shell thicknesses are synthesized and the effect of particle size and shell thickness on photocatalytic activity of TiO₂ has been investigated.

２．実験（Experimental）

First, SiO₂ cores were synthesized by the Stoeber method using TEOS as the precursor and NH₃ as the catalyst. Second, SiO₂/TiO₂ core/shell particles were synthesized. Third, hollow TiO₂ particles were synthesized by using NaOH aqueous solution at 60 °C and stirred for 24 h to remove the silica cores. Particle size and shell thickness of particles were measured by a field emission scanning electron microscopy (SEM) using JSM-7600F, JEOL, Japan. Transmission electron microscopy (TEM) images and energy-dispersive X-ray spectroscopy (EDS) mapping were taken by an aberration corrected TEM (ARM, JEOL, Japan).

３．結果と考察（Results and Discussion）

According to SEM results, all samples showed a monodisperse distribution of particles and most of the shells are intact even for the sample with the lowest thickness, 23 nm. XRD profiles of hollow TiO₂ particles showed all peaks were well consistent with the anatase crystal structure. As shown in Fig. 1, bright-field TEM image of a representative TiO₂ hollow particles, and the EDS mapping of Ti-K and O-K showed that the shell of hollow particles consists of only Ti and O atoms. The photocatalytic activity of hollow particles with different shell thickness showed that the volume of material that is able to absorb light can be the key for the different photocatalytic activity of different samples.

４．その他・特記事項（Others）

なし。

５．論文・学会発表（Publication/Presentation）

(1) H. Razavi-Khosroshahi, S. Wenhaoa, M. Fujia, Solid State Sciences 103 (2020) p.p. 106179.

６．関連特許（Patent）

なし。