Excellent room temperature catalytic activity for formaldehyde oxidation on a single-atom iron catalyst in a moist atmosphere

Abstract

For human safety, efficient removal of formaldehyde in indoor environments is essential. However, removing formaldehyde from indoor environments given the low-temperature and moisture content remains a challenge. In this study, a metal–organic framework-based single-atom iron catalyst (Fe_SA) is proposed as a candidate catalyst for formaldehyde oxidation. The adsorption characteristic and the reaction path over Fe_SA with different coordination environments were explored using density functional theory (DFT) calculation. Guided by the theoretical results, Fe_SA with 5-nitrogen coordination (Fe_SA–N₅–C) was selected and prepared for activity testing. The activity tests revealed that the removal efficiency of formaldehyde reached 85.8% at 25 °C and 75% relative humidity, which is far higher than currently reported data. More importantly, moisture can boost catalytic oxidation of formaldehyde through reduction of the energy barrier and activation of the O₂ molecule, illustrating that Fe_SA–N₅–C is robust enough for practical applications. We propose a new catalyst design route for removing formaldehyde from indoor environments, aiming for high low-temperature activity, strong water-resistance, and long-term stability.