THE EFFECT OF THE INERT SUPPORT ON RELATIVE PHOTOCATALYTIC ACTIVITY IN THE OXIDATIVE DECOMPOSITION OF ALCOHOLS ON IRRADIATED TITANIUM-DIOXIDE COMPOSITES

Reduced quantum efficiencies for the photocatalytic degradation of cyclohexanol, cyclododecanol, 2-hexanol, and benzyl alcohol are observed on TiO2 particles included within small pore zeolitic supports suspended in acetonitrile. A modest reduction in photocatalytic activity observed with TiO2 included within large pore zeolites and pillared clays is attributed to reflective and refractive losses of incident light. No appreciable substrate size selectivity could be observed in this series of supported TiO2 composites. TS-1, a titanium-containing zeolite with Ti in tetrahedral lattice sites, was photoactive, although ETS-10, a titanium-containing zeolite with Ti in octahedral lattice sites, was less so. The low quantum yield residual photoactivity observed with these alcoholic substrates on unmodified zeolites may derive from surface charge transfer complexation, as suggested by diffuse reflectance absorption measurements.