Ag Nanoparticles–Doped Co3O4 Composite Photocatalyst for UV Light–Assisted Degradation of Polystyrene Nanoplastics

Nanoplastics are a significant environmental threat due to their persistence and toxicity. In this study, we prepared a kind of Ag-doped Co 3 O 4 catalyst using a coprecipitation method, aimed at enhancing its photocatalytic degradation efficiency of polystyrene nanoplastics under UV irradiation. Morphology and component of Ag/Co 3 O 4 have been investigated by XRD, FTIR, TEM, and BET analysis. The information of absorption and energy levels for catalysts is provided by UV–vis DRS, Tauc plots, and Mott–Schottky curves. Charge-transfer abilities for catalysts have been analyzed by PL spectra and EIS. The photocatalytic activities of Ag nanoparticles (Ag NPs), Co 3 O 4 , and Ag/Co 3 O 4 have been carefully evaluated in this work. Ag/Co 3 O 4 photocatalyst exhibits the highest degradation efficiency with a kinetic rate constant of 0.0086 min − 1 , outperforming that of Co 3 O 4 (0.0062 min − 1 ) and Ag NPs (0.0036 min − 1 ). The degradation efficiencies for catalysts have also been assessed under varying pH conditions (neutral, acidic, and basic). Among them, Ag/Co 3 O 4 shows a notable degradation efficiency of 61% at pH 7, compared to 46% for Co 3 O 4 and 30% for Ag NPs. In addition, the intermediates and final products have also been discussed according to Py-GC/MS results.