Core-dual-shell structure MnO₂@Co–C@SiO₂ nanofiber membrane for efficient indoor air cleaning

Developing cost-effective and high-efficient air purification materials for enhancing the indoor air quality has been an ongoing concern. Herein, MnO₂/Co–C catalyst layers were wrapped on SiO₂ nanofiber by a combination of thermal pyrolysis and redox reaction method to prepare catalytic membranes (MCCS-x) for the efficient purification of indoor PM and HCHO. The core-dual-shell structure maintains the pore structure of the membrane, providing high gas permeability of 670 m³·m⁻²·h⁻¹·kPa⁻¹. Owing to the introduction of MnO₂/Co–C enhanced the capture of PM, the optimized MCCS-2 exhibits high filtration efficiency of PM_0.3 and PM_2.5 (99.60% and 99.99%) with a low pressure drop (<80 Pa). In addition, MCCS-2 achieves 100% HCHO removal efficiency at room temperature due to its large specific surface area, high redox property and abundant Mn⁴⁺ and oxygen species. The appropriate proportion of Mn/Co bimetallic sites synergy inhibits the formation of formate and carbonate intermediate species, thus MCCS-2 possesses excellent long-term catalytic stability than contrast sample (MCCS-3 and MS). This work demonstrates a new approach for the fabrication of high-performance catalytic membrane materials for indoor air purification.