Facile preparation of α-MnO2 nanowires for assembling free-standing membrane with efficient Fenton-like catalytic activity

Assembling MnO2 nanowires into macroscopic membrane is a promising engineered technology for catalyst separation and enhancement of Fenton-like reaction activity, yet its development is limited by the deficiencies in preparation and property modulation of the MnO2 nanowires. In this work, we developed a facile method using C2H5OH and CH3COOK as reductive and vital control reagents to react with KMnO4 by hydrothermal reaction at 140 °C for 12 h, to prepare the ultralong α-MnO2 nanowires up to tens of micrometers with high purity and aspect ratio. Such strategy not only had the advantages of being mild, easily controlled and environmental pollution-free, but also endowed α-MnO2 nanowires with excellent ability as a Fenton catalyst when assembled into free-standing membrane for degrading phenolic compounds (kobs = 0.0738 ∼ 0.1695 min−1) in a continuous flow reaction. The reactive oxygen species (i.e., •OH) from Fenton-like reaction were enriched within this α-MnO2 nanowire membrane via nanoconfinement effect, which further enhanced the mass transportation of •OH available for phenolic contaminants. MnO2 nanowire membrane using our method possessed the high practical potential for water purify due to its easy-preparation and enhanced catalytic performances.