Efficient photocatalytic degradation of an organic dye by the fabrication of a novel ternary composite based on zeolitic imidazolate framework via a facile in-situ synthetic approach

The dye contamination in waste water is a primary concern for the present sustainable society needs. Tremen-dous upsurge of industries is one of the major reasons for the increased level of dye pollution found in water systems, thus making it unfaithful for drinking and other agricultural practices. In this paper, we report a facile in-situ synthetic approach for the design of a novel ternary composite comprising of Zeolitic imidazolate framework (ZIF-8) under ambient reaction conditions. The structure, morphology, surface area and optical properties of the as-synthesized nanocomposite was studied through a number of characterization techniques including polycrystalline (or power) X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmet-Teller (BET) and ultraviolet diffused reflectance spectros-copy (UV-DRS). The as prepared composite (ZnO-CeO2@ZIF-8) showed excellent photo-catalytic activity compared to the pristine ZIF-8 for the degradation of crystal violet (CV) from aqueous medium in presence of green oxidant H2O2. Moreover, the influence of several reaction parameters such as catalyst dosage, initial so-lution pH and concentration of H2O2 were investigated on the degradation kinetics of CV. 97% degradation of CV was achieved with ZnO-CeO2@ZIF-8 in 15 min under optimized reaction conditions of catalyst dosage 12 mg and H2O2 concentration of 8 mM. The degradation of CV by ZnO-CeO2@ZIF-8 followed first order kinetics with a rate constant of 0.2373 min-1. Besides this, the active participation of hydroxyl radicals on the degradation mech-anism was confirmed by the quenching and photoluminescence studies. Also, the fabricated photocatalyst dis-played excellent stability upto 5 cycles as revealed by XRD analysis.

Automated summary

In this paper, a facile in-situ synthetic approach for the design of a novel ternary composite comprising of Zeolitic imidazolate framework (ZIF-8) under ambient reaction conditions was reported. The as-synthesized nanocomposite was characterized for its structure, morphology, surface area, and optical properties. The prepared composite showed excellent photo-catalytic activity for the degradation of crystal violet (CV), and the degradation kinetics were studied by investigating various reaction parameters. The participation of hydroxyl radicals in the degradation mechanism was confirmed, and the photocatalyst exhibited good stability for multiple cycles.