Preparation of solid acid carbon coating on the surface of TiO2 by photo-CVD of gaseous aromatic hydrocarbons

Properties of a solid acid carbon coating prepared on TiO2 powder surface using photochemical vapor deposition (photo-CVD) were evaluated. The TiO2 powder surface became brown during UV illumination under a flowing xylene and xylene sulfonic acid mixture. Observation by TEM revealed an amorphous carbon coating on the TiO2 powder. Sulfonate groups were identified on the coating using FT-IR. A chart of NH3-TPD measurements showed two peaks: that at high temperature was attributed to the coating’s strong acid. The carbon coating’s acidity was equivalent to that of the solid superacid carbon powder and the carbon-coated TiO2 decomposed cellulose.