Modulation of optical and structural properties of CoFe<subscript>2</subscript>O<subscript>4</subscript>/ZnO@CNTs for photocatalytic removal of crystal violet and phenol.

Photo-catalysis is a versatile method that is used to remediate water pollution and other issues related to the environment. Metal ferrite with a spinel structure, which is frequently used as a photocatalyst, is another solution for the remediation of environmental pollution. In this work, nanoparticles of cobalt ferrite (CoFe2O4) and zinc oxide (ZnO) were prepared by sol-gel and co-precipitation methods, respectively. CoFe2O4/ZnO (CF/ZnO) and its ternary nanocomposite with CNTs (CF/ZnO@CNTs) were fabricated by a wet-chemical approach. The prepared materials were characterized by different characterization techniques, including X-ray diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR), and UV–visible spectroscopy for the structural, functional group, and optical study respectively. Band gap values calculated for the prepared materials (CF, CF/ZnO, and CF/ZnO) were 2.45 eV, 3.37 eV, and 2.18 eV, respectively. Crystal violet and phenol were used for the evaluation of the photocatalytic efficiency of the prepared samples. In case of crystal violet photocatalytic degradation of the CF, ZnO and CF/ZnO was 21.43 %, 46.43 %, and 66.62 %, respectively. Whereas, CF/ZnO@CNTs outperformed all catalysts with 97.61 % degradation of crystal violet dye. The degradation of phenol by CF/ZnO and CF/ZnO@CNTs was 53.70 % and 83.33 %, respectively. The CF/ZnO@CNTs exhibit excellent photodegradation activity than other photocatalysts used. It is because of heterojunction fabrication and the presence of CNTs as they increase the life span of photo-generated species and enhance the surface area of the catalyst. [ABSTRACT FROM AUTHOR]