A simple and low-cost method for the preparation of self-supported TiO2-WO3 ceramic heterojunction wafers

作者:Makwana Neel M; Quesada Cabrera Raul; Parkin Ivan P; McMillan Paul F; Mills Andrew; Darr Jawwad A*
来源:Journal of Materials Chemistry A, 2014, 2(41): 17602-17608.
DOI:10.1039/c4ta03257h

摘要

Robust, bilayer heterojunction photodiodes of TiO2-WO3 were prepared successfully by a simple, low-cost powder pressing technique followed by heat-treatment. Exclusive photoirradiation of the TiO2 side of the photodiode resulted in a rapid colour change (dark blue) on the WO3 surface as a result of reduction of W6+ to W5+ (confirmed by X-ray photoelectron spectroscopy). This colour was long lived and shown to be stable in a dry environment in air for several hours. A similar photoirradiation experiment in the presence of a mask showed that charge transfer across the heterojunction occurred approximately normal to the TiO2 surface, with little smearing out of the mask image. As a result of the highly efficient vectorial charge separation, the photodiodes showed a tremendous increase in photocatalytic activity for the degradation of stearic acid, compared to wafers of the respective individual materials when tested separately.

  • 出版日期2014-11-7