Photocatalytically Active γ‐WO3 Films from Atmospheric Pressure CVD of WOCl4 with Ethyl Acetate or Ethanol

Coatings of yellow γ‐WO3 are deposited on glass by APCVD of WOCl4 and either ethanol or ethylacetate at 350–450°C. The yellow films show significant photoactivity for the destruction of stearic acid, and photoinduced superhydrophilicity. Preparation of blue reduced WO2.92 films from the same reaction at higher substrate temperatures of 500–600 °C (Figure) is also found to be possible. These films show no photoactivity, but can be converted into the fully stoichiometric photoactive form simply by heating in air.