Effect of manganese dioxide crystal structure on adsorption of SO2 by DFT and experimental study

Abstract

Based on the method of density functional theory, the adsorption properties of four different crystal forms of manganese dioxide α-, β-, γ- and δ-MnO2 for SO2 gas molecules have been studied in this paper. Through the analysis of adsorption energy and structural parameters, the most stable structure of SO2 adsorption on the surface of manganese dioxide were found, and the interaction mechanism between SO2 and surface reaction through state density, Bader charge transfer and charge density difference were studied. The results show that the adsorption energy decreased in the order: α-MnO2 ≈ γ-MnO2 > β-MnO2 > δ-MnO2. SO2 molecules interact with the surface of α-, β- and γ-MnO2 through relatively strong adsorption energy to form a stable adsorption structure, which is a chemical adsorption process. Meanwhile, the adsorption experiments of different crystalline manganese dioxide on SO2 gas have been studied. It can be seen that these metal oxides have good adsorption effects on SO2. Therefore, we hope that the results can provide some ideas for the preparation and research of catalytic oxidant for SO2 removal.