Polymer-Assisted Synthesis of Co3O4 Spinel Catalysts with Enhanced Surface Co2+ Ions for N2O Decomposition

Nitrous oxide (N2O) is a potent greenhouse gas with a global warming potential > 310 times that of CO2. Owing to its rapid increase in atmospheric concentrations from industrial emissions, N2O poses increasing environmental concerns. Among the various N2O abatement technologies, catalytic decomposition can directly convert N2O into harmless N2 and O2 without generating secondary pollutants. In this study, Co3O4 spinel catalysts were synthesized using a polymer-assisted precipitation method, using polyvinyl alcohol, polyvinylpyrrolidone, or polyethylene glycol (PEG) as N2O decomposition catalysts. The PEG-mediated synthesis method yielded the most active catalyst with superior N2O decomposition efficiency. Structural and surface analyses confirmed that PEG facilitated the formation of Co2+-enriched surface sites and abundant oxygen vacancies, which are crucial active sites for N2O adsorption and activation. Moreover, these features improved the redox properties and electron transfer behavior of the resulting catalyst. In particular, the PEG-derived 5Co3O4/CeO2 catalyst exhibited enhanced N2O decomposition activity and stability even in the presence of coexisting N2O and O2, highlighting its potential for real-world applications. This study provides an effective synthetic route for Co3O4-based catalysts and potential opportunities for wide applications in industrial N2O removal.