Electrospinning synthesis of Co3O4 porous nanofiber monolithic catalysts for the room-temperature indoor catalytic oxidation of formaldehyde at low concentrations

Room-temperature catalytic oxidation is a highly promising method for controlling formaldehyde (HCHO) concentrations indoors because it does not require any additional energy input, while completely converting HCHO into harmless H2O and CO2. This study focuses on the synthesis of Co3O4 porous nanofiber monolithic catalysts through electrospinning and investigates the mechanism behind the formation of its porous structure by analyzing the morphological changes that occur during the calcination of its fibers. In this research, we utilized heat-resistant polyacrylonitrile (PAN) as template to synthesize Co3O4 porous nanofiber monolithic catalysts. The synthesis process involved the utilization of the oxidation characteristics of PAN in the presence of cobalt acetate tetrahydrate (CH3COO)2Co·4H2O at 270–330 °C. Co3O4 porous nanofiber monolithic catalyst demonstrated exceptional performance, exhibiting over 99% catalytic activity toward HCHO at room-temperature in indoors (10–12 ppm, 25 °C) at a gas hourly space velocity of 60,000 mL·g−1h−1. This catalyst demonstrates its suitability for practical applications and its potential for energy savings. These results highlight the superiority of Co3O4 porous nanofiber monolithic catalyst over catalysts produced via the direct calcination method. The outstanding activity and stability of Co3O4 porous nanofiber monolithic catalyst make it a promising candidate for applications requiring efficient formaldehyde removal, particularly in indoors.