Preparation of TiO_2 on Ti-wires, or Fixation of Powdered TiO_2 onto Wires of Heating Element for Decomposition of Organic Wastes by Thermally-generated Holes at High Temperatures in TiO_2

摘要

Titanium dioxide was once extensively investigated as a photoconductor for the electrophotographic photoreceptor at its incunabula. Nowadays, it has attracted attention as a material for photocatalyzers, solar cells as well as their related areas. We report here another application of titanium dioxide. We are so far involved in complete decomposition of organic wastes in air by thermally-generated holes in titanium dioxide of the powdered form. In view of the practical use of the present system, fixation of TiO_2 powders onto a support in the form of, for example, a honeycomb seems to be the core technology. To realize this, we have tried in the present investigation to coat heating elements (Ti, Ni-Cr etc.) with TiO_2 powders by means of electrophoretic deposition, or to directly oxidize Ti-coated alumina ball by wet hydrogen at 980 °C. Both methods are found to be effective. Then, we have carried out decomposition experiments, with the TiO_2-coated wires or balls, of polycarbonate as well as benzene and toluene. We have confirmed that these compounds have completely been decomposed into H_2O and CO_2 by means of thermally-generated holes.