Adsorption and photocatalytic conversion of ethyl mercaptan to diethyl disulfide on Fe2O3-loaded HNbMoO6 nanosheet.

Ethyl mercaptans which commonly exist in natural gas need to be removed due to their toxic, odorous, and corrosive properties. Herein, a novel Fe2O3-modified HNbMoO6 nanosheet catalyst (Fe2O3@e-HNbMoO6) was prepared by an exfoliation-impregnation method for the ethyl mercaptans removal. In the heterojunction catalyst, e-HNbMoO6 can be excited by visible light to generate the photogenic charge and has certain adsorption property for ethyl mercaptan with hydrogen bonding (Nb-OH or Mo-OH as the hydrogen bonding donor); Fe2O3 plays the role of accelerating photogenerated electrons and holes, and enhancing the adsorption of ethyl mercaptan with another hydrogen bonding (Fe-OH as the hydrogen bonding donor and receptor). Results showed that the adsorption capacity of Fe2O3@e-HNbMoO6 is 69.9 μmol/g for ethyl mercaptan. In addition, the photocatalytic conversion efficiency of ethyl mercaptan to diethyl disulfide is nearly 100% and it is higher than that of the other Nb-Mo based photocatalysts, such as LiNbMoO6, Fe1/3NbMoO6, Ce1/3NbMoO6, TiO2-HNbMoO6, e-HNbMoO6, CeO2@e-HNbMoO6, and Ag2O@e-HNbMoO6. Under the experimental conditions, the photocatalytic conversion efficiency is greater than the adsorption efficiency over Fe2O3@e-HNbMoO6, and there is no ethyl mercaptan output in the process of adsorption and photocatalytic conversion. Fe2O3@e-HNbMoO6 heterojunction catalyst has practical value and reference significance for purifying methane gas and enhancing photocatalytic conversion of ethyl mercaptan.