Influence of Pt dispersibility and chemical states on catalytic performance of Pt/CeO2-TiO2 catalysts for VOCs low-temperature removal

Abstract

Catalytic oxidation at low temperature has been considered as an effective technology for the volatile organic compounds (VOCs) elimination. Among many catalysts, the supported noble metal catalysts are the most widely used in practical application, but the correlation between the dispersibility and chemical states of noble metals and the catalytic activity is still unclear. In this paper, four Pt/CeO2-TiO2 catalysts with high catalytic activity of VOCs low-temperature removal were prepared by various methods and systematically evaluated. It is found that the activities of the Pt/CeO2-TiO2 catalysts for the complete oxidation of benzene depend on Pt dispersion, Pt chemical states and Oads./Olatt proportion in the catalysts. The high Pt dispersion (especially Pt single atom dispersion) obviously enhances the interaction between Pt and CeO2-TiO2, resulting in the formation of more Pt2+ and absorbed oxygen species, which promotes the catalytic activity for benzene oxidation. The Pt/CeTi-EFD catalyst prepared by electron free deposition (EFD) method exhibits excellent oxidation activity with T90 % as low as 150 °C for benzene, and possesses satisfying adaptability for various VOCs oxidation and good stability. The large amount of the Pt4+ species has an adverse effect for catalytic oxidation of benzene, leading to the poor oxidation activity. This comprehensive consideration should be very helpful when designing and preparing novel catalysts for the low-temperature removal of VOCs.