New insight into the design of highly dispersed Pt supported CeO2-TiO2 catalysts with superior activity for VOCs low-temperature removal

A series of CeO 2 –TiO 2 mixed oxides supports with various Ce/Ti molar ratio were synthesized by modified coprecipitation method. The corresponding Pt loaded (0.5 wt% Pt) catalysts were prepared by electronless deposition method and evaluated for the deep oxidation of n -hexane as a model VOCs. The results show that the CeO 2 and TiO x nanoparticles can highly disperse into each other and form Ce 2 Ti 2 O 7 solid solution with appropriate Ce/Ti molar ratio, which significantly improves their redox ability by enhancing the interaction between CeO 2 and TiO x . The dispersibility of Pt species can also be adjusted by altering the Ce/Ti molar ratio, and Pt/CeTi-2/1 catalyst with Ce/Ti molar ratio of 2:1 exhibits the best Pt dispersibility that Pt species mainly exist as Pt single atoms. The high dispersion of Pt species in the Pt/CeO 2 –TiO 2 catalysts would promote the catalytic activity of VOCs oxidation with low T 90% values (1000 ppm, GHSV = 15,000 h −1 ), such as for n-hexane degradation with T 90% of 139 °C. The characterizations reveal that the superior activity is mainly related to possessing the more Pt 2+ species, adsorbed oxygen species and higher low-temperature reducibility owing to the strong interaction between highly dispersed Pt species and CeO 2 –TiO 2 as well as the promoted migration of lattice oxygen by the formation of more Ce 2 Ti 2 O 7 species. Furthermore, the Pt/CeTi-2/1 catalyst also exhibits excellent stability for chlorinated and other non-chlorinated VOCs oxidation, making it very promising for real application under various operating conditions. • Pt/CeO 2 –TiO 2 catalysts with high oxidation activity for VOCs are synthesized. • Microstructure of catalysts is carefully analyzed by the WRF Refinement method. • High dispersion of Pt species accelerates the degradation of VOCs oxidation. • The SMSI between Pt SAs and support increases the dispersion and stability of Pt. • Formation of Ce 2 Ti 2 O 7 promotes the migration of lattice oxygen species.