Ruthenium (Ru) nanoparticles (∼3 nm) with mass loading ranging from 1.5 to 3.2 wt % are supported on a reducible substrate, cerium dioxide (CeO, the resultant sample is called Ru/CeO), for application in the catalytic combustion of propane. Because of the unique electronic configuration of CeO, a strong metal-support interaction is generated between the Ru nanoparticles and CeO to stabilize Ru nanoparticles for oxidation reactions well. In addition, the CeO host with high oxygen storage capacity can provide an abundance of active oxygen for redox reactions and thus greatly increases the rates of oxidation reactions or even modifies the redox steps. As a result of such advantages, a remarkably high performance in the total oxidation of propane at low temperature is achieved on Ru/CeO. This work exemplifies a promising strategy for developing robust supported catalysts for short-chain volatile organic compound removal.
Deactivation of CeO2‐based catalysts in the HCl oxidation reaction proceeds via selective bulk chlorination of the active CeO2 component to form CeCl3×nH2O. We study the reactivation of two bulk‐chlorinated CeO2‐based Deacon catalysts by oxygen treatment at 430 °C, namely pure CeO2 and 20 mol % of CeO2 supported on preformed ZrO2 particles (20CeO2@ZrO2), with a dedicated experiment. In the flow reactor setup we determine in‐situ the degree of chlorination of the catalyst by quantifying down‐stream with in‐situ UV‐Vis spectroscopy the total amount of chlorine in the catalyst that is exchanged by reoxidation at 430 °C. The activity of deactivated 20CeO2@ZrO2 can be fully restored by oxygen exposure at 430 °C, while that of pure CeO2 declines steadily. Since the UV‐Vis analytics is fast and sensitive, we can follow the kinetics of reoxidation. To rationalize the observed kinetics, we develop a modified Johnson‐Mehl‐Avrami‐Kolmogorov (JMAK) model based on a nucleation‐and‐growth approach for the reoxidation of the catalyst starting from the chlorinated phase. The fast reoxidation kinetics of chlorinated 20CeO2@ZrO2 is traced to a fast nucleation rate.
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