Cux Ce1-xO2 nanoflake type catalysts with improved catalytic activity and good thermal stability for diesel soot combustion

Title : Cux Ce1-xO2 nanoflake type catalysts with improved catalytic activity and good thermal stability for diesel soot combustion

Abstract:

In the present study, nanoflakes (NF) of CeO2 -NF and Cux Ce1-xO2 -NF (x = 0.1, 0.2, 0.3 and 0.4) were prepared with the polyvinylpyrrolidone(PVP)-assisted co-precipitation method. The prepared samples were first characterized with FE-SEM, HR-TEM, XRD, N2 adsorption, O2 -TPD, H2 -TPR, Raman and XPS. Then, their catalytic performance and thermal stability were examined for the applications in soot combustion. It was found that Cux Ce1-xO2 -NF exhibited much better activity in tight contact mode than CeO2 -NF that has no Cu doping. Furthermore, the highest activity was observed for the sample of Cu0.2Ce0.8O2 -NF, which was most likely due to its moderate doping that induced both a large amount of surface adsorbed oxygen species and a special flake morphology, thus providing effective contact area. However, in NOx -assisted loose contact mode, the catalysts exhibited relatively lower activity with a T50higher than that of tight contact mode due to the reduced solid-solid contact points. Finally, both the cyclic and accelerated aging tests demonstrated that Cu0.2Ce0.8O2 -NF was able to keep a good thermal stability.

Audience Take Away:

• Nanoflakes of CeO2 -NF and Cu0.2Ce0.8O2 -NF were synthesized with the PVP-assisted co-precipitation method.
• Doping of Cu in CeO2 -NF significantly promoted the formation of oxygen species that replenished the vacancies.
• Cu0.2Ce0.8O2 -NF exhibited superior catalytic performance in soot oxidation with a T50 as low as 312 °C for tight contact mode and 360 °C for loose contact mode.
• Cu0.2Ce0.8O2 -NF kept good catalytic activity and thermal stability after five cycles or the accelerated aging tests.

Biography:

Dr. Liu studied Chemical Engineering at Dalian University of Technology, China, graduated with BS and MS degree in 1985 and 1988 respectively. He then joined the College of Chemical Engineering at East China University of Science of Technology as an Assistant Professor and worked for six years before going to US for pursuing advanced study. He received his PhD degree in 1998 from Oklahoma State University, and then worked in industries (in US companies like Chevron) for more than 12 years before returned to China and became a Professor at Xiamen University in 2010. Dr. Liu’s research areas include Biomass & Bioenergy, Hydrogen Production & Fuel Cells, and Environmental Catalysis. He has published more than 60 research papers, and holds 10 US patents and more than 20 Chinese Patents.