Template-free synthesis of stable cobalt manganese spinel hollow nanostructured catalysts for highly water-resistant CO oxidation

Summary Development of spinel oxides as low-cost and high efficiency catalysts is highly desirable, however, rational synthesis of efficient and stable spinel systems with precisely controlled structure and components remains challenging. We demonstrate the design of complex nanostructured cobalt-based bimetallic spinel catalysts for low temperature CO oxidation by a simple template-free method. The self-assembled multi-shell mesoporous spinel nanostructures provide high surface area (203.5 m2/g) and favorable unique surface chemistry for producing abundant active sites and lead to creation of robust microsphere configured by 16nm spinel nanosheets, which achieve satisfactory water-resisting property and catalytic activity. Theoretical models show that O vacancies at exposed {110} facets in cubic spinel phase guarantee that reactive oxygen species strongly adsorbed on the surface of catalysts and play a key role in preventing deactivation under moisture rich conditions. The design concept with architecture and composition control can be extended to other mixed transition metal oxide compositions.