The volatile organic compounds (VOCs) from cooking oil fumes are very complex and do harm to humans and the environment. Herein, we develop the high-efficiency and energy-saving synergistic photothermocatalytic oxidation approach to eliminate the mixture of heptane and hexanal, the representative VOCs with high concentrations in cooking oil fumes. The Pt/CeO2/TiO2 catalyst with nanosized Pt particles was prepared by the simple hydrothermal and impregnation methods, and the physicochemical properties of the catalyst were measured using numerous techniques. The Pt/CeO2/TiO2 catalyst eliminated the VOC mixture at low light intensity (100 mW cm-2) and low temperature (200 °C). In addition, it showed 25 h of catalytic stability and water resistance (water concentration up to 20 vol %) at 140 or 190 °C. It is concluded that O2 picked up the electrons from Pt to generate the •O2- species, which were transformed to the O22- and O- species after the rise in temperature. In the presence of water, the •OH species induced by light irradiation on the catalyst surface and the •OOH species formed via the thermal reaction were both supplementary oxygen species for VOC oxidation. The synergistic interaction of photo- and thermocatalysis was generated by the reactive oxygen species.
Keywords: cooking oil fumes; heptane and hexanal oxidation; reactive oxygen species; synergistic photothermocatalytic oxidation; water resistance.