NiCo2O4 hollow microsphere-mediated ultrafast peroxymonosulfate activation for dye degradation

Morphology and dispersity are key factors for activating peroxymonosulfate (PMS). In this study, we designed a recyclable open-type NiCo2O4 hollow microsphere via a simple hydrothermal method with the assistance of an NH3 vesicle. The physical structure and chemical properties were characterized using techniques such as scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), N-2 adsorption and X-ray photoelectron spectroscopy (XPS). The test results confirm that the inner and outer surfaces of open-type NiCo2O4 hollow-sphere can be efficiently utilized because of the hole on the surface of the catalyst, which can minimize the diffusion resistance of the reactants and products. Under optimized conditions, the total organic carbon (TOC) removal efficiency of rhodamine B (RhB) can reach up to 80% in 40 min, which is almost 50% shorter than the reported values. The reactive radicals were identified and the proposed reaction mechanism was well described. Moreover, the disturbances of HCO3-, NO3-, Cl- and H2PO4 were further investigated. As a result, HCO3- and NO3- suppressed the reaction while Cl- and H2PO4 had a double effect on reaction. (C) 2021 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences. Published by Elsevier B.V. All rights reserved.

Automated summary

The study focuses on the design of a recyclable open-type NiCo2O4 hollow microsphere with enhanced TOC removal efficiency for rhodamine B, and investigates the impact of various interfering substances on the reaction. The proposed reaction mechanism and the utilization of the catalyst's surface structure are highlighted in the study.