PM-support interfacial effect and oxygen mobility in Pt,Pd or Rh-loaded (Ce,Zr,La)O2 catalysts |
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Authors: | Ting Wang Renxian Zhou |
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Institution: | Institute of Catalysis, Zhejiang University, Hangzhou 310028, China |
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Abstract: | ? Pt/CZL exhibits the optimum catalytic performance for HC and NOx elimination. ? The strong PM-Ce interaction favors the oxygen mobility and DOSC. ? Pd/CZL shows higher catalytic activity for CO conversion due to more Olatt species. ? Great oxygen mobility at high temperature broadens the dynamic operation window. ? The relationship between DOSC and catalytic performance is revealed. The physicochemical properties of Pt-, Pd- and Rh- loaded (Ce,Zr,La)O2 (shorted for CZL) catalysts before/after aging treatment were systematically characterized by various techniques to illustrate the relationship of the dynamic oxygen storage/release capacity and redox ability with their catalytic performances for HC, NOx and CO conversions. Pt/CZL catalyst exhibits the optimum catalytic performance for HC and NOx elimination, which mainly contribute to its excellent redox ability and dynamic oxygen storage/release capacity (DOSC) at lower temperature due to the stronger PM (precious metals)-support interaction. However, the worse stability of Pt-O-Ce species and volatile Pt oxides easily result in the dramatical decline in catalytic activity after aging. Pd/CZL shows higher catalytic activity for CO conversion by reason of more Olatt species as the active oxygen for CO oxidation reaction. Rh/CZL catalyst displays the widest dynamic operation window for NOx elimination as a result of greater oxygen mobility at high temperature, and the ability to retain more Rh-O-Ce species after calcined at 1100°C effectively restrains sintering of active RhOx species, improving the thermal stability of Rh/CZL catalyst. |
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Keywords: | Precious metal-loaded (Ce Zr La)O2 catalysts Oxygen mobility Catalytic performance |
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