Synthesis of cuboid-type tungsten trioxide photocatalysts for oxygen evolution from water in the presence of silver(I) sulfate under visible light irradiation

• Published in: Materials research bulletin 2018-06, Vol.102, p.56-61
• Main Authors: Kaneyama, Yuka, Tanaka, Atsuhiro, Sanada, Tomoe, Kominami, Hiroshi, Kojima, Kazuo
• Format: Article
• Language: English
• Subjects: A. Inorganic compounds; A. Oxides; B. Optical properties; CALCINATION; CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; D. Catalytic properties; HYDROTHERMAL SYNTHESIS; IRRADIATION; OXYGEN; PHOTOCATALYSIS; REACTION KINETICS; SILVER SULFATES; SPECIFIC SURFACE AREA; TUNGSTEN OXIDES; VISIBLE RADIATION; WATER
• ISSN: 0025-5408; 1873-4227
• DOI: 10.1016/j.materresbull.2018.02.017

[Display omitted] •Visible-light photocatalytic cuboid-type tungsten trioxide (C-WO3) particles were prepared by calcination at various temperatures between 200 and 500 °C.•Photocatalysis of the prepared C-WO3 samples was investigated for oxygen evolution from water in the presence of sacrificial silver(I) sulfate.•The photocatalytic activity differed among the samples and the sample calcined at 400 °C showed the top activity.•The main factor influencing the photocatalytic activity of the C-WO3 was determined. We synthesized various cuboid-type tungsten trioxide (WO3) particles using a hydrothermal method followed by calcination at various temperatures between 200 and 500 °C. Visible-light photocatalysis of these particles was investigated for oxygen (O2) evolution from water in the presence of sacrificial silver(I) sulfate. The calculated crystallite diameters increased with increasing calcination temperature, suggesting that the level of crystallinity increased with calcination temperature. The average specific surface area of the particles was almost the same for all calcination temperatures in the range 200–400 °C, but was decreased at 500 °C. The photocatalytic reaction rate of O2 formation increased with increasing calcination temperature up to 400 °C, and then decreased as calcination temperature was further increased to 500 °C. We therefore concluded that the rate increased with calcination temperature up to 400 °C due to the increasing crystallinity, but then decreased due to the decreased specific surface area.