Z-scheme charge transfer heterostructure with NiV2O6@gC3N4 nanocomposite: A competent photocatalyst for boosting the photodegradation of antibiotics

초록

Background: Photocatalytic removal of antibiotic pollutants from wastewater is essential for environmental protection and human health. Constructing a Z-scheme platform with nanocomposites can be an effective strategy to attain high degradation efficiency in photocatalytic systems for the sustainable elimination of antibiotics. Methods: In the present work, we developed a novel Z-scheme heterostructure based on the nanocomposite of NiV2O6@gC3N4 (NVO@gCN) for degrading antibiotics, viz., Ciprofloxacin (CIP) and Norfloxacin (NF). NVO nanopebbles (NPs) were synthesized through the coprecipitation route. NVO@gCN was produced via synthesizing gCN by direct heat treatment, and subsequent anchoring of different concentrations of NVO (10, 30, and 50 wt%) on the gCN surface using the ultrasonic method. Significant findings: The physicochemical characteristics of the NVO@gCN heterostructure were analyzed by various techniques to reveal their aptness for antibiotic degradation. The structural and morphology studies confirmed the presence of a strong contact between sheet-like gCN layers and NVO NPs. The oxygen vacancies present in the heterostructure improved efficient charge carrier separation and activation of O2 molecules. Optical and photoelectrochemical results proved that the charge transfer efficacy was enhanced for the heterostructures. The optimum NVO30@gCN heterostructure exhibited degradation efficiencies of about 93.90 % and 91.16 % for CIP and NF in 120 min, respectively. Furthermore, total organic carbon (TOC) removal efficiencies of 71.7 % for CIP and 75.2 % for NF degradation were attained by the heterostructure, revealing a high mineralization degree. Free radical capture tests exposed the contribution of center dot O2- and center dot OH radicals to the photodegradation process, which was further confirmed by electron spin resonance (ESR) spectroscopy. In addition to that, according to the energy band potentials of the NVO@gCN heterostructure, a plausible charge transfer mechanism was discussed. This study provides an effective approach for constructing the Z-scheme heterostructure for photocatalytic water treatment applications.

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