Remarkable MnO2 structure-dependent H2O promoting effect in HCHO oxidation at room temperature

Chunyan Ma; Shumei Sun; Hao Lu; Zhengping Hao; Chenggong Yang; Bin Wang; Cheng Chen; Maoyong Song

doi:10.1016/j.jhazmat.2021.125542

Remarkable MnO₂ structure-dependent H₂O promoting effect in HCHO oxidation at room temperature

J Hazard Mater. 2021 Jul 15:414:125542. doi: 10.1016/j.jhazmat.2021.125542. Epub 2021 Feb 26.

Authors

Chunyan Ma¹, Shumei Sun², Hao Lu³, Zhengping Hao⁴, Chenggong Yang¹, Bin Wang⁵, Cheng Chen¹, Maoyong Song⁶

Affiliations

¹ Key Laboratory of Environmental Nanotechnology and Health Effects, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
² Department of Physics and Applied Optics Beijing Area Major Laboratory, Beijing Normal University, Beijing 100875, China.
³ Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany.
⁴ University of Chinese Academy of Sciences, Beijing 100049, China.
⁵ Beijing Research Institute of Chemical Industry, Sinopec Group, Beijing 100013, China.
⁶ Key Laboratory of Environmental Nanotechnology and Health Effects, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China. Electronic address: smsong@rcees.ac.cn.

PMID: 33667806
DOI: 10.1016/j.jhazmat.2021.125542

Abstract

H₂O is often critical in determining the activity and stability of metal oxide catalysts for HCHO oxidation; however, synthesis of metal oxide catalysts with super resistance to H₂O remains a challenging. Herein, we synthesized Akhtenskite-type MnO₂ catalyst with Mn-O-Mn stretching along MnO₆ octahedra layers, which promotes the utilization of the associatively adsorbed H₂O. The activity and stability of formaldehyde oxidation at room temperature enhanced in humid air. Diffuse-reflectance infrared Fourier transform (DRIRFT) spectroscopy was used to characterize the H₂O adsorption and intermediate species. The associatively adsorbed H₂O promotes the oxidation of formaldehyde to CO₂ via the formic acid intermediate. The service life of MnO₂ is prolonged due to formic acid generation. MnO₂ gradually deactivates when formic acid accumulates and forms formate and hydrogen carbonate species. This study provides significant insights into the development of a high-efficiency MnO₂ catalyst for formaldehyde oxidation in humid air, and the developed MnO₂ catalyst is a promising candidate for application in practical formaldehyde elimination.

Keywords: HCHO oxidation; MnO(2) structure; Room temperature; Structure-dependent H(2)O effect.