One-step fabrication of electrospun flexible and hierarchically porous Pt/γ-Al2O3 nanofiber membranes for HCHO and particulate removal

Abstract

The removal of harmful formaldehyde (HCHO) pollutants in indoor air is of great importance to protect human health. Herein, a flexible Pt/γ-Al₂O₃ (PAO) nanofiber membrane with a hierarchically porous structure was prepared by a one-step electrospinning method. The effects of Pt contents and calcination temperatures on the catalytic performance for HCHO oxidation at room temperature were investigated. The results indicate that Pt nanoparticles (NPs) are firmly decorated on the surface of γ-Al₂O₃ nanofibers since the loading of Pt NPs and the preparation of γ-Al₂O₃ nanofibers are conducted at the same time. PAO can oxidize HCHO to CO₂ and H₂O completely at room temperature. The catalytic activity of PAO first increases and then decreases with increasing Pt content or calcination temperature. The Pt content of 2 wt% and the calcination temperature of 700 °C are the optimal preparation parameters. The catalytic activity of PAO maintains good stability in 6 cycling tests after a simple regeneration heat treatment at 180 °C. The dioxymethylene, CO, carbonate and formate species are the main intermediates. The mechanism for HCHO oxidation was proposed as follows: HCHO + O₂ → DOM and formate → carbonate species and CO → CO₂. PAO also exhibits good flexibility and mechanical properties, good filtration performance for particulate matter and good fluid permeability. This work will shed a light on the design and fabrication of bifunctional catalytic materials for both HCHO and particulate matter removal in air purification.