ALD-seeded hydrothermally-grown Ag/ZnO nanorod PTFE membrane as efficient indoor air filter

It has been well recognized that there are a number of indoor contaminants including particulate matter, gaseous pollutants and microbials. The removal of indoor contaminants often requires multiple layers of various air filters. Herein, we report on a multifunctional air purifying filter produced by the hydrothermal growth of ZnO nanorod-wrapped PTFE nanofibers, constructed of nanostructured Ag deposited on the ZnO nanorods with a hierarchical structure for gas contaminant removal. Atomic layer deposition (ALD) was used to seed a layer of ZnO nanoseeds onto the PTFE fibrils which were then subjected to a hydrothermal reaction to form ZnO nanorods. Ag nanoparticels were subsequently assembled on the surface of the ZnO nanorods via a silver electroless deposition reaction. The resulting composite membrane exhibited an excellent dynamic antibacterial property of ~100% and a formaldehyde degradation rate of 60%. Compared with the pristine membrane, the gas permeation of the composite membrane increased from 227.26 m³ m⁻² h⁻¹ kPa⁻¹ to 275.36 m³ m⁻² h⁻¹ kPa⁻¹. The successful fabrication of this composite membrane with remarkable antibacterial and excellent formaldehyde degradation performance may provide a new route for the preparation of indoor air purification filters.