Engineering Zr-Metal Organic Framework-Based Binary Composite Using Facile In Situ Strategy for Photocatalytic Degradation of Multiple Dyes: Synergistic Effect and Mechanistic Insight

Abstract

Although metal–organic frameworks (MOFs) have promising photocatalytic properties such as high surface area and customisable pore architectures, their practical applicability is frequently hampered by the rapid recombination of photogenerated charge carriers, which reduces degradation efficiency. To overcome this constraint, several approaches to integrating MOFs with light-responsive semiconductors have been investigated. This study used a Zr-based MOF with ZnCo₂O₄ to create a highly effective photocatalyst. The goal was to improve charge separation and photocatalytic performance. The resultant composite demonstrated exceptional degradation efficiencies of 82.27% for Bismarck Brown (BB) and 94.24% forRose Bengal (RB) under natural sunlight within 55 min, with optimal catalyst doses of 0.47 g/L. The composite's structural, morphological and optical properties were fully investigated utilising SEM–EDX, HRTEM, PXRD, FTIR, XPS, BET and UV-DRS techniques. The photodegradation process followed first-order kinetics, with rate constants of 0.0371 min⁻¹ and 0.06544 min⁻¹ for BB and RB, respectively. Photoluminescence (PL) spectroscopy, VB-XPS and scavenger quenching investigations provided mechanistic insights into successful charge separation and reactive species formation. The ZnCo₂O₄@UiO-66 composite is highly recyclable, with consistent XRD patterns confirming stable photocatalytic efficacy across five cycles. These findings emphasise the composite's potential as a strong and reusable MOF-based photocatalyst for efficiently removing dye contaminants in environmental remediation applications.