Complex Three-Dimensional Co₃O₄ Nano-Raspberry: Highly Stable and Active Low-temperature CO Oxidation Catalyst

Area of Science:

• Materials Science
• Catalysis
• Nanotechnology

Background:

• Noble metal catalysts are effective but costly for carbon monoxide (CO) oxidation.
• Simple cobalt oxide (Co₃O₄) nanoparticles aggregate and sinter during reactions, reducing stability and activity.
• Developing complex, stable nanostructures without noble metals is crucial for sustainable catalysis.

Purpose of the Study:

• To synthesize highly stable and active low-temperature CO oxidation catalysts using non-noble metals.
• To overcome the challenge of nanoparticle aggregation and sintering in catalytic reactions.
• To establish a synthesis method for complex, ordered three-dimensional nanostructures.

Main Methods:

• Hydrothermal treatment of cobalt glycolate solution with sodium sulfate.
• Synthesis of 100 nm raspberry-shaped Co₃O₄ nanoparticles (7-8 nm primary size).
• Utilizing sulfate ions as bridging ligands to control self-assembly and particle growth.

Main Results:

• Formation of Co₃O₄ nano-raspberry structures with large surface area (89 m²·g⁻¹) and abundant oxygen vacancies.
• Sulfate ions effectively suppressed particle growth and aggregation.
• Catalyst demonstrated high stability at 350 °C and achieved nearly 100% CO conversion at room temperature.

Conclusions:

• Bridging ligands are effective for controlling the formation of stable, complex 3D nanostructures.
• The synthesized Co₃O₄ nano-raspberry catalyst offers high thermal and chemical stability.
• This approach provides a pathway for developing high-performance, non-noble metal catalysts for CO oxidation.