Assembly of MOFs derived Co-Mn bimetallic oxides on SiO₂ nanofibrous membrane for indoor air purification

The development of highly efficient air purification materials contributes to acquiring quality indoor air that essential for improving physical health and life comfort. In this work, a Co₃O₄-CoMn₂O₄@SiO₂ (COCMOS) nanofibrous membranes (NFMs) were prepared by thermal treating Mn-modified ZIF-67@SiO₂ NFMs for efficient indoor air purification. The COCMOS NFMs exhibited 99.03 % and 99.999 % dust retention efficiencies for PM_0.3 and PM_2.5 with a low filtration resistance, respectively. Compared to the Co₃O₄@SiO₂ (COS) NFMs (23 %), the HCHO removal efficiency of COCMOS NFMs was significantly improved at room temperature, reaching over 95 % within 25 min. The characterization results indicated that the thermal treatment of Mn-modified ZIF-67 induced the formation of a Co₃O₄-CoMn₂O₄ heterostructure on the surface of COCMOS NFMs. The Mn-Co bimetallic sites in this heterogeneous structure increased the amounts of oxygen vacancies and high valent cations and enhanced the redox properties of COCMOS NFMs, which contributed to its superior performance. This work provided insights on the design and preparation of highly efficient materials for indoor air purification.