Preparation of M/Ce1-xTixO2 (M=Pt, Rh, Ru) from sol-gel method and their catalytic oxidation activity for diesel soot

A series of Ce1-xTixO2 mixed oxide catalysts were synthesized by sol-gel method and then loading of noble metal (M = Pt, Rh, Ru) was used for soot oxidation. Ti-doped Ce1-xTixO2 catalysts (x is the molar ratio of Ti/(Ti + Ce) and ranges from 0.1 to 0.5) exhibit much better oxidation performance than CeO2 catalyst, and the Ce0.9Ti0.1O2 catalyst calcined at 500 degrees C has the best catalysis activity. Each noble metal (1 wt%) was supported on Ce0.9Ti0.1O2 (M/C9T1) and the properties of the catalysts were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman, BrunauereEmmetteTeller (BET) method, and H-2-temperature programmed reduction (H-2-TPR) results. Results show that the introduction of Ti into CeO2 forming Ti-O-Ce structure enhances the catalytic activity and increases the number of oxygen vacancies at the catalyst surface. The noble metal is highly dispersed over Ce0.9Ti0.1O2, and M/C9T1 catalysts present enhanced activity in comparison to Ce0.9Ti0.1O2. It is found that noble metals can greatly increase the activity of the catalyst and the corresponding oxidation rate of soot can enhance the electron transfer capacity and oxygen adsorption capacity of the catalyst. A small amount of Ti doping in CeO2 can significantly improve the activity of the catalyst, while a large amount of Ti reduces the performance of the catalyst because a large amount of Ti is enriched on the surface of the catalyst, which hinders the contact and reaction between the catalyst and the soot. (c) 2021 Chinese Society of Rare Earths. Published by Elsevier B.V. All rights reserved.

Automated summary

A series of Ce1-xTixO2 mixed oxide catalysts were synthesized using sol-gel method and noble metal loading for soot oxidation. The Ti-doped Ce1-xTixO2 catalysts exhibited better oxidation performance than CeO2, with the Ce0.9Ti0.1O2 catalyst showing the highest catalysis activity when calcined at 500 degrees C. The introduction of Ti into CeO2 enhanced the catalytic activity and increased the number of oxygen vacancies on the catalyst surface. Noble metals dispersed over Ce0.9Ti0.1O2 showed enhanced activity compared to Ce0.9Ti0.1O2. A small amount of Ti doping improved the catalyst activity, while excessive Ti reduced performance due to hindered contact and reaction with soot.