Crystal-facet dependent CO oxidation, preferential oxidation of CO in H2-rich, water-gas shift reactions, and supercapacitor application over Co3O4 nanostructures

•Co3O4 nanoplates and nanologs were synthesized.•CO oxidation and preferential oxidation of CO under H2-rich condition were tested.•Water-gas shift reaction and supercapacitor properties were examined.•Nanoplates with {112}-exposed facets showed better performance in all the tests.

Tailoring the exposed crystal facet of a material is a very important strategy for improving the application performance. Herein, cubic phase Co3O4 with two different morphologies, nanoplates and nanologs, was synthesized, and CO oxidation, preferential oxidation of CO (CO-PROX) under H2-rich condition, water-gas shift (WGS) reaction, and supercapacitor properties were examined. The nanoplates with {112}-exposed facets showed better performance in all the test model systems. The {112} facets contained more active Co3+, which is responsible for the activation of CO oxidation (and H2 production) at a lower temperatures. A facial ion transport on the facet increased the specific capacitance of the plates. The wider application tests and the design of Co oxide nanostructures provide a better strategy for the development of Co-based materials.

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