Fabrication of mixed-ligand ZIF-8-derived mesoporous ZnO for enhanced photocatalytic activities for methylene blue and naphthol degradation

ZnO is widely recognized as an effective photocatalyst for degradation organic waste. However, their nonporous nature presents a significant challenge. This study introduces a novel approach to address this limitation by employing a mixed-ligand strategy using 2-methylimidazole (2-MeIM) and 2-aminoterephthalic acid (NH₂-BDC). This method creates a new ZIF-8 framework that serves as a template for mesoporous ZnO. The results show that ZnO derived from mixed ligands has a significantly larger pore size (79.14 nm) than that derived from single ligands (13.81 nm), enhancing its ability to adsorb methylene blue (MB) and naphthol during the pre-photocatalytic process. Photoluminescence tests revealed that ZnO with mixed ligands emitted less light, indicating fewer recombination events, contributing to its superior photocatalytic performance. ZnO from mixed ligands was able to degrade ∼97.18 of MB in 90 min and ∼100 % of naphthol in 60 min. Economically, producing ZnO with mixed ligands is more cost-effective than commercial alternatives while offering superior performance. After reuse, the degradation efficiency of ZnO with mixed ligands decreased slightly to 90.06 % over the same period. This study provides a new perspective on how mixed ligands can serve as templates to create mesoporous ZnO with improved photocatalytic activity for organic waste degradation, making it a promising strategy for sustainable environmental applications.