Bimetallic Co-Fe and Co-Cr oxide systems supported on CeO2: Characterization and CO oxidation catalytic behaviour

摘要

Bimetallic catalysts of Co-Cr and Co-Fe supported on CeO2 are examined with respect to their behaviour towards CO oxidation. The decomposition of the precursors of the samples under air was examined by thermogravimetric/differential thermal analysis (TG/DTA) in order to determine adequate calcination temperature to apply during preparation of the catalysts. Samples calcined at 800 degrees C are characterized by measurement of specific surface area (S-BET), X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) techniques in comparison with selected monometallic references. The characterization results are employed as a basis to explain catalytic activity results for CO oxidation. While the Co-Cr system does not enhance the activity of the corresponding monometallic Co reference catalyst, Fe is shown to promote low temperature activity, affected to some extent by a deactivation mechanism. Details of the iron promoting effect as well as the deactivation process are examined by operando-DRIFTS experiments which show that the presence of trace water in the feeding gases appreciably affects the catalytic performance of the systems. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.