Ceramic Fiber Paper-Based Manganese Oxides Catalyst for Room Temperature Formaldehyde Oxidation

The catalytic removal of trace formaldehyde (HCHO) at ambient temperatures is crucial for improving indoor air quality, necessitating the use of monolithic catalysts over traditional powder forms for real-world applications. In this study, an aluminosilicate fiber-woven ceramic filter paper (CFP) was selected as the substrate, onto which a Mn 2 O 3 catalyst was in situ coated via a combustion method utilizing Mn(NO 3 ) 2 as the oxidant and glycine as the fuel. The resulting monolithic Mn 2 O 3 /CFP catalyst was compared to a MnO 2 /CFP catalyst, prepared by direct decomposition of Mn(NO 3 ) 2 on the same substrate. The Mn 2 O 3 /CFP catalyst exhibited superior characteristics for HCHO oxidation, including a more porous architecture, higher redox capability, and an abundance of surface-active oxygen species with enhanced mobility of surface lattice oxygen. These features enabled the Mn 2 O 3 /CFP catalyst to achieve significantly higher HCHO conversion at room temperature (90%) compared to the MnO 2 /CFP catalyst (21%). Additionally, in a durability test carried out in a mode of dynamic flow at room temperature, the Mn 2 O 3 /CFP catalyst maintained a high HCHO conversion rate of 66% over 11 days, demonstrating its potential for practical indoor air purification applications. Graphical abstract