Catalytic oxidation of carbon monoxide by α-alumina supported 3 nm cerium dioxide nanoparticles

Alumina supported 3 nm cerium dioxide nanoparticles (ceria NPs) have been found to efficiently catalyze the oxidation of carbon monoxide to carbon dioxide in the presence of excess oxygen. Complete conversion of CO to CO2 was achieved in a 44.5 mL/min flow of 7739 ppm CO +/- 2%, 41,500 ppm 02 2%, and helium as balance at 400 degrees C with low catalyst loadings. The activity of unsupported ceria NPs was greatly reduced, presumably due to sintering. Supported 3 nm ceria NPs were also found to be much more active than commercially available ceria micro-powder. Without prior thermal activation, supported 3 nm ceria NPs were found to lower the light-off temperature for CO oxidation by 200 and 100 degrees C compared to inactivated and activated ceria micro-powders, respectively. The ease with which this catalyst can be prepared from commercially available resources and its high reactivity indicates that this material shows promise as a means of lowering CO emissions from automobiles without increasing precious metal loadings in catalytic converters. (C) 2017 Elsevier B.V. All rights reserved.