shows that CO2 and H2O appeared to be the main gas
component in the treated gas stream with a small amount of
untreated toluene. The suspected intermediates of straight chain
hydrocarbons and CO were very minimal or undetectable in the
treated gas stream. Some colour changes were observed on the
surface of the TiO2–SiO2 materials, indicating that oxidation
intermediates may be formed at the surface of the catalyst. Further
study of its speciation and how to minimise these reactions
are recommended.