Green Synthesis and Applications of Cobalt Oxide Nanoparticles

Cobalt oxide nanoparticles (Co₃O₄ NPs) have emerged as versatile materials owing to their spinel structure, mixed valence states and tunable surface chemistry. Green synthesis harnesses plant extracts, microorganisms or other biological agents to reduce metal precursors under mild conditions, thereby minimising hazardous reagents and energy input. The resulting biogenic Co₃O₄ NPs often display controlled size, morphology and surface functionality, which are critical for performance in diverse applications. In environmental remediation, these nanoparticles act as effective photocatalysts for degrading organic pollutants under visible light, thanks to their narrow band gap and high surface area. In biomedical fields, Co₃O₄ NPs exhibit promising antibacterial and antioxidant activities, while surface modifications enable targeted delivery or enhanced cytotoxicity against cancer cells. Moreover, their electrochemical properties lend themselves to sensor development, energy storage and catalysis. Together, these capabilities underscore the global significance of green-fabricated cobalt oxide nanomaterials in advancing sustainable technologies across environmental, health and energy sectors.

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Green Synthesis and Applications of Cobalt Oxide Nanoparticles publication trend

The graph below shows the total number of articles in green synthesis and applications of cobalt oxide nanoparticles across all publications each year (not limited to Nature Index journals).

Technical terms

Nanoparticle: A particle with at least one dimension between 1 and 100 nm, exhibiting size-dependent properties distinct from bulk material.

Green synthesis: A suite of eco-friendly fabrication methods that employ biological agents or extracts as reducing and stabilising agents for nanoparticle production.

Photocatalysis: A light-driven process wherein a semiconductor absorbs photons to generate charge carriers that drive redox reactions on its surface.

Band gap energy: The energy difference between the valence and conduction bands in a semiconductor, determining the wavelengths of light it can absorb.

Calcination: A thermal treatment process that induces phase transitions, removes organic residues and alters crystallinity and surface chemistry of nanoparticles.

References

1. Green synthesis of cobalt oxide nanoparticles and the effect of annealing temperature on their physiochemical and biological properties. Materials Research Express (2021).
2. Green Synthesis and Characterization of Cobalt Oxide Nanoparticles Using Psidium guajava Leaves Extracts and Their Photocatalytic and Biological Activities. Molecules (2022).