Recent advances on Co3O4-based nanostructure photocatalysis: Structure, synthesis, modification strategies, and applications

Advanced oxidation processes, mainly photocatalysis, are utilized as an effective and alternative prospect for industrial wastewater treatment, especially in the non-biodegradable compounds. Among various photocatalysts, Co3O4 is a visible light active photocatalyst that exhibits superb photocatalytic activity in various photocatalytic applications. However, photocatalytic activity of bare Co3O4 nanoparticles remains inacceptable because of inherent shortcomings such as rapid recombination. Significant efforts were done in the last several years to advance performance and figure out the mechanisms involved. This review begins with structural & optical properties (and DFT studies), synthesis methods and goes detail about recent advances and strategies for refining the performance of Co3O4-based photocatalysts, for instance structural design and creation of Co3O4-based composites. Construction of Co3O4-based heterojunction results in a distinct photogenerated photocarriers mechanism, which reduces the recombination and increases photoactivity. The sole emphasis of this review is on the latest developments in environmental applications for Co3O4 as well as photocatalysts based on them. In conclusion, the varied environmental applications of Co3O4-based materials, such as pollutant degradation (i.e., dyes, antibiotics, phenols, pesticides, and Cr (VI) reduction) and energy conversion (e.g., H2 production, CO2 reduction/CO evolution, and O2 evolution), are summarized in detail. To summarize the bottlenecks, exciting challenges, current progress, and future perspectives for innovative opportunities are also presented.