Abstract
High demand of an efficient photocatalyst to degrade the antibiotics is one of the major challenges for industrial applications. Herein, the CQDs sensitized NiFe2O4 spheres anchored CoCr2O4/MoO3-x NSs with high doxycycline (DOXY) photodegradation efficiency were successfully prepared via co-precipitation, hydrothermal-calcination assisted methods. The abundant oxygen defects and synergistic effect of the photocatalyst contributed to its excellent photodegradation efficiency (99.70 % at pH 6) with a rate constant of 0.0388 min−1 under visible light irradiation. The kinetic study revealed that the interfacial engineered NFO/CQDs co-decorated MoO3-x/CCO composite have 13.30, 5.87, and 7.05 times greater efficiency than the pristine MoO3, CCO, and NFO respectively. The n-p-n heterojunction formed under the action of internal electric field at the interface have greatly suppressed the charge carrier recombination. Meanwhile, the enlarged specific surface area (342.70 m2/g) provided more active sites to improve the reaction. The superoxide radical (O2−), and hydroxyl radical (OH) played crucial role in the DOXY degradation process, as affirmed by radical trapping experiment and ESR analysis. Moreover, the crystalline structure, bonding energy and photodegradation ability remained unchanged after six consecutive cycles indicating excellent recyclability, and stability for practical applications. The toxicity of the end products was investigated against E. coli and S. epidermis, revealing the complete mineralization of the antibiotics, and further confirmed by ecotoxicity analysis. The dual vacancy enriched (surface decorated and intrinsic O-vacancies) NFO/CQDs co-decorated MoO3-x/CCO composite exhibited remarkable stability, structural and catalytic properties providing an insight into the efficient photocatalytic degradation of pharmaceutical pollutants.
[Display omitted]
•NiFe2O4/CQDs decorated MoO3-X/CoCr2O4 composite fabricated via calcination-hydrothermal assisted methods.•Internal electric field induced n-p-n heterojunction enhanced separation of e−/h+ pairs.•Composite exhibited 13.3 folds enhanced photocatalytic performance than the MoO3.•Toxicity assessment was performed against bacterial species.•Excellent practical applicability for antibiotic degradation.