Improved ceria-based support with enhanced Pt-CeO2 interaction leading to higher activity and stability for catalytic emission control reactions

Fudong  Liu, University of Central Florida

Improved ceria-based support with enhanced Pt-CeO2 interaction leading to higher activity and stability for catalytic emission control reactions

Wei Tan1,2, Hatim Alsenani1, Yandi Cai2, Shaohua Xie1, Fudong Liu1,*, Fei Gao2,*, Lin Dong2

1Department of Civil, Environmental, and Construction Engineering, Catalysis Cluster for Renewable Energy and Chemical Transformations (REACT), NanoScience Technology Center (NSTC), University of Central Florida, Orlando, FL 32816, United States

2Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Jiangsu Key Laboratory of Vehicle Emissions Control, School of Environment, Center of Modern Analysis, Nanjing 210093, P. R. China

 

*Corresponding E-mail address: fudong.liu@ucf.edu (F. Liu); gaofei@nju.edu.cn (F. Gao)

Phone: +1-407-823-6219 (F. Liu); +86 25 83596545 (F. Gao)

 

Pt catalysts supported on ceria-based materials have been widely studied and applied in industrial application. Among them, Pt single site catalysts have aroused widespread concern because of 100% Pt atomic utilization1-2. The interaction between Pt and CeO2 significantly determined the catalytic performance of Pt/CeO2 based catalysts. It has been reported that the surface defects on the supports contributed to the formation and stabilization of single atom catalysts3-4. The intrinsic nature of CeO2 supports such as particle size, crystallinity or exposed crystal facets should also have a significant impact on the performance of Pt/CeO2 based catalysts in various reactions.

In this work, using a CeO2 colloidal solution as precursor, a unique CeO2/Al2O3 (CeC/Al) support containing small CeO2 particles with uniform particle size (~10 nm) was successfully synthesized. When compared to the regular CeO2/Al2O3 support using Ce(NO3)3·6H2O as precursor (CeN/Al), the CeO2 particles on CeC/Al was much smaller, and more surface defects were observed on CeC/Al as well. After Pt loading, it was found that Pt was better dispersed on CeC/Al in single site form, which was mainly related to the smaller CeO2 size and richer surface defects on this new support. Much higher concentration of Pt-O-Ce structure was observed on Pt/CeC/Al than on Pt/CeN/Al, indicating the stronger interaction between Pt and CeO2 on Pt/CeC/Al. After H2 activation, Pt/CeC/Al-a catalyst (a = activation) showed much higher CO oxidation activity than that of regular Pt/CeN/Al-a. After aging treatment under air (800 oC, 12 h), Pt/CeC/Al-800A-a still performed better CO removal efficiency than Pt/CeN/Al-800A-a. This work provided a new strategy to design a new ceria-based support with controllable CeO2 particle size, which could be used as a promising and industrially scalable support for platinum group metal (PGM) catalysts (Pt, Pd, Rh etc.) or transition metal catalysts (Cu, Co etc.) to achieve better catalytic performance.

Figure 1. a) Raman spectra of CeC/Al, CeN/Al, Pt/CeC/Al and Pt/CeN/Al; b) CO oxidation activity on Pt/CeC/Al-a and Pt/CeN/Al-a catalysts before and after aging treatment.

Reference:

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