Development of evaluation method for photocatalytic ability by ion chromatography combined with a flow-type reactor; Application to immobilized photocatalyst materials prepared by double-layer coating method

Sugita, Tsuyoshi; Kobayashi, Kentaro*; Yamazaki, Taiki*; Isaka, Mayu*; Itabashi, Hideyuki*; Mori, Masanobu*

Journal of Photochemistry and Photobiology A; Chemistry, 400, p.112662_1 - 112662_8, 2020/09

https://doi.org/10.1016/j.jphotochem.2020.112662

In this study, we developed an in-line photocatalytic performance evaluation system in which a flow reactor was connected to the ion chromatography to accurately evaluate the performance of the photocatalyst. This system was used to evaluate the photocatalyst supported by the two-layer support method on the substrate, such as glass beads. The performance of the photocatalyst was evaluated using dimethyl sulfoxide (DMSO), and it was possible to monitor the decomposition of DMSO by UV and the formation of by-products, such as methane sulfonate (MSO) and sulfate (SA). This system can be expected to be useful not only for evaluating the decomposition performance of an object using a photocatalyst but also for evaluating the byproducts.

Blister formation in rutile TiO (100) thin films by helium ion implantation

Yamamoto, Shunya; Nagata, Shinji*; Takeyama, Akinori; Yoshikawa, Masahito

Transactions of the Materials Research Society of Japan, 30(3), p.789 - 792, 2005/09

no abstracts in English

Photocatalytic properties of S-doped TiO under visibel light irradiation

Umebayashi, Tsutomu; Asai, Keisuke*; Yamaki, Tetsuya; Yoshikawa, Masahito

Kogyo Zairyo, 51(7), p.34 - 36, 2003/07

https://ci.nii.ac.jp/naid/80015964818

no abstracts in English

Sulfur-doping of rutile-titanium dioxide by ion implantation; Photocurrent spectroscopy and first-principles band calculation studies

Umebayashi, Tsutomu; Yamaki, Tetsuya; Yamamoto, Shunya; Miyashita, Atsumi; Tanaka, Shigeru; Sumita, Taishi*; Asai, Keisuke*

Journal of Applied Physics, 93(9), p.5156 - 5160, 2003/05

https://doi.org/10.1063/1.1565693

Sulfur (S)-doped titanium dioxide (TiO) was synthesized by ion implantation and subsequent thermal annealing. Compared to the pure TiO, a photocurrent was observed in the lower energy regions for the S-doped TiO. Based on the theoretical analyses by the first principles band calculations using the full potential linearized augmented plane wave methods within the generalized gradient approximation, the mixing of the S 3p states with the valence band (VB) was found to contribute to the increasing width of the VB. This leads to the bandgap narrowing in the S-doped TiO. Therefore, the photon-to-carrier conversion was induced during irradiation by visible light above 420 nm ( 2.9 eV).

Visible light-induced degradation of methylene blue on S-doped TiO

Umebayashi, Tsutomu; Yamaki, Tetsuya; Tanaka, Shigeru; Asai, Keisuke*

Chemistry Letters, 32(4), p.330 - 331, 2003/04

https://doi.org/10.1246/cl.2003.330

A sulfur (S)-doped titanium dioxide (TiO) photocatalyst was synthesized by oxidative annealing of titanium disulfide (TiS). TiS turned into anatase TiO when annealed in air. The residual S atoms occupied O-atom sites in the TiO to form Ti-S bonds. The S doping caused the absorption edge of TiO to be shifted into the lower energy region. Consequently, methylene blue adsorbed on the S-doped TiO was photocatalytic decomposed by visible light irradiation.

Band gap narrowing of titanium dioxide by sulfur doping

Umebayashi, Tsutomu; Yamaki, Tetsuya; Ito, Hisayoshi; Asai, Keisuke*

Applied Physics Letters, 81(3), p.454 - 456, 2002/07

https://doi.org/10.1063/1.1493647

Titanium dioxide (TiO) doped with sulfur (S) was synthesized by oxidation annealing of titanium disulfide (TiS). According to the X-ray diffraction patterns, TiS turned into anatase TiO when annealed at 600 C. The residual S atoms occupied O-atom sites in TiO to form Ti-S bonds. The S doping caused the absorption edge of TiO to be shifted into the lower energy region. Based on the theoretical analyses using ab-initio band calculations, mixing of the S 3p states with the valence band was found to contribute to the band gap narrowing.

Characterization of epitaxial TiO films prepared by pulsed laser deposition

Yamamoto, Shunya; Sumita, Taishi; Yamaki, Tetsuya; Miyashita, Atsumi; Naramoto, Hiroshi

Journal of Crystal Growth, 237-239(Part1), p.569 - 573, 2002/04

The epitaxial growth of TiO films has attracted much interest from the viewpoints of basic science and applications. In the present study, it is shown that TiO films with anatase or rutile structure can be grown by pulsed laser deposition(PLD) with an ArF excimer laser under the controlled O atmosphere. The TiO films were prepared on the LaAlO, LSAT SrTiO and -AlO single crystal substrates. The epitaxial films were analyzed by RBS and X-ray diffraction for investigating the crystallographic relationships with the substrates. The high quality anatase TiO(001) films have been successfully grown on the LaAlO (001), LSAT (001) and SrTiO (001) substrates at temperatures above 500C. Also the high quality rutile TiO(100) and (001) films were obtained on the -AlO (0001) and (10-10), respectively.The optical properties were characterized by optical absorption measurements. The optical band gaps for anatase and rutile TiO epitaxial films were evaluated to be 3.22 eV and 3.11 eV, respectively.

A New characterization method of photocatalytic activity in semiconductor photocatalysts

Sumita, Taishi; Yamaki, Tetsuya; Yamamoto, Shunya; Miyashita, Atsumi

Japanese Journal of Applied Physics, Part 1, 40(6A), p.4007 - 4008, 2001/06

https://doi.org/10.1143/JJAP.40.4007

We propose a new simple method for characterizing photocatalytic activity by measuring photo-generated transient charge separation at the surface of semiconductor photocatalysts. In this method, the charge separation generated by a pulse dye laser is obtained as a function of the incident laser energy. Using this method, the photocatalytic activity and the type of surface reaction (reduction or oxidation) in titanium dioxide films were rapidly determined.

None

*

PNC TJ8625 96-001, 28 Pages, 1996/03

PNC-TJ8625-96-001.pdf:0.97MB

no abstracts in English

Synthesis of photocatalytic minerals by clay mineral salt insertion method

Sugita, Tsuyoshi; Mori, Masanobu*; Shimoyama, Iwao

no journal, , 

This study investigates the conversion of biotite, a subgroup of clay minerals, into photocatalysts through heat treatment with CaCl. The resulting reaction products were analyzed in terms of their composition, structure, optical properties, and photocatalytic activity against Cr(VI) and salicylic acid (SA). Biotite and CaCl mixtures could be heated to 600C while retaining the biotite crystal structure, whereas heating to 700C resulted in transformation to octahedral wadalite crystals. The band gap of the wadalite obtained after heat treatment was approximately 3.10 eV. The photocatalytic reduction rate per unit surface area increased markedly with increasing heat-treatment temperature, and the Cr(VI) reduction and SA degradation rates of the sample calcined at 800C were approximately 18 and 9 times greater, respectively, than those of the sample calcined at 500C. Leaching tests of the reaction products revealed that the elution of Ca and Cl was particularly significant. Even the samples that retained the biotite structure after heat treatment displayed some photocatalytic activity, indicating that this method may be applicable to preparing photocatalysts from mica and related minerals with similar structures.

光触媒の製造方法、還元方法、及び光触媒

杉田 剛; 下山 巖

not registered

JP, 2020-107863  Patent licensing information

【課題】入手が容易な材料から環境負荷の低い方法で光触媒を製造する方法を提供する。 【解決手段】粘土鉱物と塩とを混合し、500℃以上で加熱することによる、光触媒の製造方法。前記光触媒と金属化合物を混合し、光を照射することによって、前記金属化合物を還元することを特徴とする前記金属化合物の還元方法。