Hierarchical MnO2-ZnO functionalized SiO2 nanofibrous membranes with enhanced Fenton-like catalytic performance for dye removal

In this work, flexible and hierarchical structured MnO2-ZnO/SiO2 nanofibrous membranes (NFMs) as easily recyclable Fenton-like catalysts have been developed utilizing the combination of electrospinning and a hydrothermal growth method. By capitalizing the advantages of the high specific surface area and synergism effects of bimetallic oxides, the optimal membranes exhibited prominent catalytic activity in the degradation of malachite green oxalate (MGO). Specifically, within a mere 15 min at an initial pH, 98.1% of MGO was degraded, demonstrating a remarkable degradation rate of 0.2744 min-1. Free radical scavenging experiments and Electron Paramagnetic Resonance studies conclusively identified superoxide radical species (O2 center dot-) as the main reactive species for the degradation of MGO. Furthermore, the resultant flexible membranes displayed excellent stability and could be effortlessly recycled after catalytic process, surpassing the performance of conventional powdery Fenton-like catalysts. Notably, the resultant membranes could be used for dynamic catalyst for MGO removal and could efficiently treat 418 mL MGO with a flux of 5650.5 L m-2 h-1. The successful fabrication of these MnO2ZnO/SiO2 membranes paves the way for the development of more efficient and applicable Fenton-like catalytic materials for water treatments and offers more inspirations for innovative designs of fiber-based or membranebased catalysts.