Substitutional C and interstitial N in MnO2/NC catalysts enable high performance of formaldehyde oxidation at room temperature

Abstract

Formaldehyde (HCHO) is a harmful gas that dangers the health of human kind. Catalytic oxidation provides a green approach converting HCHO to harmless CO2. In this work, we designed MnO2 catalysts by co-doping NC for HCHO catalytic elimination. The substitutional C and interstitial N in the MnO2 activate the surface lattice oxygen and weaken the Mn-O bond strength. The more active surface lattice oxygens and the more active adsorbed dioxygen species at the oxygen vacancies result in the greater HCHO oxidation performance over the MnO2/NC catalysts doping with NC than the MnO2 catalysts without doping. The performance enhancement is dependent on the crystal phase of MnO2, HCHO is fully converted at 30 ℃ over α-MnO2/NC catalyst, followed by 35 °C over the γ-MnO2/NC catalyst. The higher performance of the α-MnO2/NC catalyst is associated with its higher BET surface area, more active surface lattice oxygen and adsorbed dioxygen species than those of the γ-MnO2/NC catalyst. This work verifies the more effective HCHO elimination performance of MnO2-based catalysts by co-doping NC, and the strategy is applicable for other related oxidative reactions.