| Abstract Scope |
Cobalt oxide nanoparticles, particularly spinel Co₃O₄, have emerged as promising visible-light-responsive photocatalysts owing to their narrow band gap, mixed-valence electronic configuration, excellent chemical stability, and earth abundance. Nevertheless, their photocatalytic performance remains constrained by rapid electron–hole recombination, limited charge mobility, and suboptimal utilization of visible light. Recent studies demonstrate that engineering the electronic structure provides one of the most effective strategies for overcoming these limitations. By tailoring the density of electronic states, Co˛⁺/Coł⁺ redox distribution, defect chemistry, band structure, and interfacial charge redistribution, electronic structure engineering enhances light absorption, charge separation, carrier transport, and surface catalytic reactions. This mini-review critically discusses the fundamental principles of electronic structure engineering in cobalt oxide nanoparticles, recent advances in electronic modulation strategies, current challenges, and future directions for designing high-performance photocatalysts for environmental remediation and solar-energy conversion. |