Journal Article

Alkali Metal Doped MnOx Catalysts for Formaldehyde Oxidation

Liu, Hao, Liu, Yenan, Zhao, Hailin, Chu, Xiutang

2025

Overview

The catalytic oxidation of formaldehyde to CO 2 and H 2 O under low temperature is of great significance and insistent demand for indoor air purification. In this work, through alkali metal doping, we significantly improved the formaldehyde oxidation activity of Mn-based catalysts. At a temperature as low as 97 °C, 300 ppm of formaldehyde can be completely eliminated over 5%Cs/MnO x . The results showed that the presence of alkali metals markedly increased the redox ability of MnO x catalyst and the proportion of reactive oxygen species. The adsorption and reaction path of formaldehyde on the surface of the catalysts were studied by in-situ infrared spectroscopy. It was found that the adsorption form of formaldehyde on the surface of alkali metals doped MnO x catalyst was different from that of MnO x , except for monodentate formate detected over MnO x , more easily decomposed bridged adsorbed formate was another prominent adsorbed species over 5%Na/MnO x and 5%Cs/MnO x catalysts. The difference in reaction paths may be the key to the higher activities of alkali doped MnO x catalysts. This finding may provide some new ideas for the design of low temperature formaldehyde oxidation catalysts. Graphical Abstract The intermediate species during formaldehyde oxidation on MnO x and Na + /Cs + -doped MnO x are different, which may be the key reason why the latter exhibit higher activities than MnO x .

• Publisher: Springer US,Springer Nature B.V
• Subject: Adsorption / air / Air purification / Alkali metals / carbon dioxide / Catalysis / Catalysts / Catalytic oxidation / Cesium / Chemistry / Chemistry and Materials Science / Decomposition reactions / Formaldehyde / formates / Industrial Chemistry/Chemical Engineering / infrared spectroscopy / Low temperature / Organometallic Chemistry / Oxidation / Physical Chemistry / reactive oxygen species / species / temperature