The different evolution behaviors of carbonate-like species on Pt/CeO2 and Pt/Al2O3 by in situ DRIFTS-MS study

• DOI: 10.1016/j.cattod.2021.11.009
• Publication Date: 2021-11-15T16:34:27Z
• Authors: Xiaoqing Feng; Zilin Wang; Long Mu; Zhilin Chen; Jinhu Liang; Chao Xiao
• Keywords: Reactivity; Diffuse reflection; Reaction intermediate

Abstract No consensus has been reached on the role of reducible and irreducible supports on the reaction pathway of CO oxidation over supported metal catalysts. Here, colloidal ligand-free Pt nanoparticles were deposited on Al2O3 and CeO2 to investigate the support effect in CO oxidation by in situ diffuse reflectance Fourier-transform infrared spectroscopy (DRIFTS) and mass spectrometry (MS). On Pt/Al2O3, the carbonate-like intermediates accumulate and do not decompose to CO2 at the ignition temperature (150 °C) or above; the conversion of CO to CO2 follows classic Langmuir−Hinshelwood (L–H) mechanism with direct reaction of CO and O2 on Pt. Whereas for Pt/CeO2, the CO conversion to bidentate carbonate (b-CO32−) species followed by decomposition to CO2 is a main reaction pathway leading to its high reactivity at low temperature (75 °C). CeO2 facilitates the activation of oxygen to produce the carbonate-like intermediates and further decomposition to CO2, which resulted in a lower ignition temperature.