Fabricating an oxygen-vacancy-rich urchin-like Co3O4 nanocatalyst to boost peroxymonosulfate activation to degrade high-concentration crystal violet

• Published in: Ceramics international Vol. 48; no. 18; pp. 26553 - 26564
• Main Authors: Li, Bo, Xu, Huan-Yan, Liu, Yu-Long, Dong, Li-Min, Komarneni, Sridhar
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15.09.2022
• Subjects: Co3O4; Degradation pathway; Morphology; Oxygen vacancy; Peroxymonosulfate; Reaction mechanism; Reaction mechanism; Peroxymonosulfate; Morphology; Degradation pathway; Co3O4; Oxygen vacancy
• ISSN: 0272-8842; 1873-3956
• DOI: 10.1016/j.ceramint.2022.05.351

Due to the in-situ generation of reactive oxygen species (ROS), sulfate radical-based advanced oxidation processes (SR-AOPs) have emerged for the oxidative degradation of organic contaminants. Developing highly efficient heterogeneous catalysts is of great importance for SR-AOPs. In this work, an urchin-like Co3O4 nanocatalyst with oxygen vacancies (VO) was elaborately fabricated and employed for enhanced peroxymonosulfate (PMS) activation to degrade the high-concentration active dye crystal violet (CV). The obtained sample was characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and N2 adsorption/desorption isotherms. Characterization results indicated that this unique VO-rich urchin-like Co3O4 nanocatalyst was endowed with a larger surface area and abundant reactive sites for PMS adsorption and activation. The experimental results of CV degradation showed that nearly complete removal of 100 mg L−1 CV could be realized within 30 min of reaction time under neutral conditions at room temperature, and the degradation process followed retarded-first-order kinetics. Electron paramagnetic resonance (EPR) spectra accompanied by quenching experiments of radicals demonstrated that the contribution of ROS to CV degradation followed this sequence: 1O2 > ▪OH > SO4▪- > O2▪-. The degradation pathways of CV were proposed by a combination of density functional theory (DFT) calculations along with frontier orbit theory while the toxicity of intermediate products was evaluated by quantitative structure-activity relationship (QSAR) prediction. [Display omitted] •Oxygen-vacancy-rich urchin-like Co3O4 was fabricated for PMS activation.•Active radicals were confirmed by radical quenching tests and EPR technology.•Radical 1O2 dominated crystal violet degradation by a nonfree radical pathway.•The degradation pathways of CV were simulated by DFT calculations.•The toxicity of intermediate products was evaluated by QSAR prediction.