Novel Zn(II)-imidazolate polymorph MOF loaded with Mo-QD clusters for solar light-driven H2O2-assisted synergistic photosensitized degradation of gentian violet

Abstract

Herein, a novel molybdenum-incorporated Zn(II)-imidazolate-based metal-organic framework polymorph material was fabricated through a facile technique as an effective photocatalyst for the removal of gentian violet (GV) from an aqueous medium. The structure, composition, morphology, and optical properties. were evaluated using XRD, SEM, TEM, XPS, SAED, UV-DRS, PL, and elemental mapping. The average diameter of the Mo QDs incorporated into the MOF sheet matrix was calculated to be 6 nm using TEM. The zeolitic framework thus synthesized, exhibited a nearly complete degradation of gentian violet (99.6 %) under solar irradiation within 30 min. The photodegradation followed pseudo-first-order kinetics with a remarkable reaction rate constant of 0.241 min−1. The effect of various reaction parameters and the presence of other competing species was also studied in a detailed investigation to emphasize the effectiveness of the photocatalyst in different environments. A series of scavenging experiments, EPR analysis, and LC-MS analysis was performed to identify the reactive species and the reaction pathway for the photodegradation of GV. The hydroxyl (•OH) and superoxide (•O2-) radicals played a primary role in the degradation of GV through AOP. The enhanced efficiency of as-synthesized Mo@ZIF polymorph may be due to a synergistic effect of direct and a photosensitized dye degradation mechanism. The photocatalyst showed good recyclability with 89.5 % efficiency up to 4 cycles. The research findings thus suggest that the Mo@ZIF polymorph photocatalyst may have a significant potential for solar energy harvesting and subsequent environmental remediation via an advanced oxidation process.