Cobalt oxide-based catalysts supported on zirconia fibers synthesized by atomic layer deposition

Abstract

This work is focused on the synthesis and evaluation of cobalt oxides grown onto zirconia fibers by the Atomic Layer Deposition (ALD) technique. CO oxidation is a wide studied reaction so that it was used as a model for testing the synthesized catalysts. Morphological and physicochemical properties were investigated through various characterization techniques. The deposited loading of the active phase was low (<1.2 at.% in all samples), and it was dispersed homogeneously along the zirconium oxide with fiber morphology with an length/diameter aspect ratio of about 50. Bulk and surface analysis showed the presence of different cobalt species (Co2+ and Co3+) that allow obtaining active catalysts for the reaction under study. Both the total amount of cobalt and the proportion of Co3+ species were higher as the number of ALD cycles increased. Through stability experiments, a change in the active species was detected after various cycles of reaction. This modification led to an increase in the surface Co3+ amount with changes in the coordination state.