Morphology-Controlled Fabrication of Co₃O₄ Catalysts and Performance Towards Low Temperature CO Oxidation

Abstract: This article reports the heterogeneous catalysis of CO oxidation over nanostructured Co₃O₄ at low temperatures. The hydrothermal method was deftly exploited to fabricate nanostructured Co₃O₄ with three kinds of precipitants (i.e., urea, hexamethylene tetramine, and sodium hydroxide), which were thoroughly characterized with XRD, BET, TEM/SEM, HR-TEM, H₂-TPR, and XPS to understanding the correlation between the morphology of Co₃O₄ and the corresponding catalytic performance. Specifically, the straw-like nanorods, flower-like nanosheets, and honeycomb-like nanoparticles of Co₃O₄ could be controlled with the choice precipitants. Our comprehensive analysis indicated that the straw-like Co₃O₄ nanorods possessed preferential performance for CO catalytic oxidation among these nanostructured Co₃O₄ to produce CO₂. In addition, the results showed good long-term stability for practical application over the straw-like Co₃O₄ nanorods and showed no significant decay (the activity maintained 97% conversion) within 50 h at 125 °C. The novel insights of low-temperature CO oxidation on nanostructured Co₃O₄ from this work could hold promise for the development of new strategies and design principles for manufacturing highly active and stable catalysts. Graphic Abstract: [Figure not available: see fulltext.]