PM-support interfacial effect and oxygen mobility in Pt, Pd or Rh-loaded (Ce,Zr,La)O2 catalysts

The physicochemical properties of Pt-, Pd- and Rh- loaded (Ce,Zr,La)O-2 (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 O-latt 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 degrees C effectively restrains sintering of active RhOx species, improving the thermal stability of Rh/CZL catalyst. (C) Higher Education Press 2020

Automated summary

The physicochemical properties and catalytic performances of Pt/CZL, Pd/CZL, and Rh/CZL catalysts were systematically characterized to illustrate the relationship between their dynamic oxygen storage/release capacity, redox ability, and catalytic activities for HC, NOx, and CO conversions. The study found that Pt/CZL exhibited the best catalytic performance for HC and NOx elimination due to its excellent redox ability and dynamic oxygen storage/release capacity, while Pd/CZL showed higher catalytic activity for CO conversion and Rh/CZL had the widest dynamic operation window for NOx elimination.