A novel NH2-MIL-125/dandelion-like MnO2 nanosphere composite with a rapid interfacial electron transfer pathway for photocatalytic degradation of ornidazole

The effectiveness of photocatalysis is constrained by the insufficient efficiency of charge separation, migration, and utilization that are generated by light. Enhanced photocatalytic efficiency is significantly achieved through the important technique of integrating Metal-Organic Frameworks (MOFs) with other materials to form heterojunction structures. In this study, NH2-MIL-125/MnO2 (NMM) composite photocatalyst has been designed, featuring a Z-scheme heterojunction structure with enhanced interfacial charge transfer and an improved lifetime of charges. The physicochemical properties of the NMM composite were analysed by multiple techniques. The photocatalytic efficiency of the NMM composite is notably superior to pristine NH2-MIL-125 and MnO2. This enhanced performance can be credited to the improvement in the recombination rate, charge transfer resistance, and adsorption site, as revealed by the characterization data. The photocatalytic performance of the NMM composite was analysed for ornidazole antibiotics degradation, which showed 91.31 % degradation efficiency at optimum conditions. In the photocatalytic degradation mechanism, center dot O-2(-) free radicals were the major oxidative species responsible for the ornidazole degradation.