Cobalt ferrite nanoparticles for the preferential oxidation of CO

In the present study cobalt ferrite (CoFe2O4) nanoparticles have been successfully prepared through the glucose-assisted hydrothermal method. We verified that the use of glucose is highly advantageous for the synthesis in order to prevent particle agglomerates as well as to obtain single-phase CoFe2O4 nanoparticles. The H-2-TPR results showed that the CoFe2O4 indicates the reduction of CoO to Co degrees and of Fe2O3 to Fe3O4 followed by the reduction of Fe3O4 to metallic iron Fe. XPS observations evidenced the presence of Fe3+ and Co2+ and practically exclude the existence of Fe2+ and Co3+ species at the surface. In situ DRIFTS-MS showed formate species at 100 degrees C which increased with increasing temperature due to the reaction between CO gas and hydroxyl groups of cobalt ferrite. The as-prepared material exhibited high CO conversion and good stability on stream at 250 degrees C during 30 h. In addition, it has been observed that the cobalt ferrite catalyst is inhibited by the presence of H2O and CO2, although a totally reversible process, but have no influence on the chemical structure of the surface active sites. (C) 2016 Elsevier B.V. All rights reserved.