Microwave synthesis of mesoporous WO3 doping with bismuth and photocatalytic oxidation of water to H2

Abstract

Mesostructured tungstic acid was prepared from Na 2 WO 4 with protonated cation-exchange using a surfactant cetyltrimethyl ammonium bromine (CTAB) as the structure-directing agent under microwave radiation. The surfactant was removed by high-temperature calcination, microwave radiation extraction and Soxhlet extraction, respectively. The effects of these methods for removal of the surfactant were investigated in detail. XRD, TEM, FT-IR and UV-Vis were employed to characterize the mesostructured materials. The results showed that the microwave extraction and Soxhlet extraction were favorable to the synthesis of mesostructured tungstic oxide. Mesoporous structure was destroyed as the calcining temperature rising to 823 K. The mesoporous structure of WO 3 prepared by microwave radiation extraction had an average pore diameter of 3.4 nm and specific surface area of 120.46 m 2 ·g −1 . And also, the mesoporous materials WO 3 doping with Bi 2 O 3 displayed much higher photocatalytic activity than commercial Degussa P25 TiO 2 under visible light and UV irradiation.

Synthesis of Tungstate Oxide/Bismuth Tungstate Composite and Application in Microbial Fuel Cell as Superior Low-Cost Cathode Catalyst than Platinum

“…3, the IR bands appeared at the wavenumber of 764 cm −1 , 754 cm −1 and 609 cm −1 for WO 3 , are the characteristics intensity peaks of Keggin structure of as-synthesized WO 3 . 50 These characteristic peaks of tungsten oxide are associated to the terminal vibration (764 cm −1 ), corner-sharing vibration (754 cm −1 ) and superoxide vibration (609 cm −1 ). In addition, W-O-W stretching vibration could be easily noticed at wavenumber of 600 cm −1 and 1,000 cm −1 .…”

Photocatalytic Semiconductors

“…A great variety of synthesis route (see Chap. 3) are used for the synthesis of doped semiconductors which included mainly coprecipitation (Liu et al 2005), sol-gel (Jaimy et al 2011), hydrothermal (Jiang et al 2014), solvothermal , Pechini method (Wang and Cao 2011), combustion (Ahmad et al 2013), microwave (Li et al 2014a), ultrasound (Omidi et al 2013, and in the form of thin films by sol-gel (Wang and Cao 2011) deposited by dip coating (Zou et al 2011).…”

“…For this purpose, Zou et al (2011) reported the microwave synthesis of mesoporous Bi-doped WO 3 materials in presence of cetyltrimethyl ammonium bromine (CTAB) as structure-directing agent. The amount of Bi 2 O 3 loading was optimized in a 7.0 wt % for the production of H 2 .…”