Abstract
Sulphide gas is an impurity that affects the quality of natural gas, which needs reasonable storage and transportation. In this work, we investigated the adsorption structure and electronic behavior of hydrogen sulfide (H2S), carbonyl sulfur (COS), and methyl mercaptan (CH3SH) on sulphide gas molecules on pure and vacant α-Fe2O3(001) surfaces by density functional theory with geometrical relaxations. The results show that H2S and CH3SH are mainly adsorbed in the form of molecules on the pure Fe2O3(001) surface. On the vacant α-Fe2O3(001) surface, they can be adsorbed on Fe atoms in molecular form and by dissociation. The absolute value of the adsorption energy of H2S and CH3SH on the vacancy defect α-Fe2O3 surface is larger, and the density of states show that the electron orbital hybridization is more significant, and the adsorption is stronger. The charge differential density and Mulliken charge population analysis show that the charge is rearranged and chemical bonds are formed. The affinity of H2S to the vacancy α-Fe2O3(001) surface is slightly higher than that of CH3SH, while COS molecules basically do not adsorb on the α-Fe2O3(001) surface, which may be related to the stable chemical properties of the molecules themselves.
Highlights
As one of the most important energy sources, natural gas has been more and more widely used in the past few decades [1,2]
Some sulphide gas impurities will inevitably be introduced into the exploitation of natural gas, such as hydrogen sulfide (H2S), carbonyl sulfur (COS), and methyl mercaptan (CH3SH) [3,4,5]
The results show that H2S and CH3SH are mainly adsorbed in the form of molecules at the Fe top site, and the adsorption energies are −0.56 eV and −0.50 eV, respectively
Summary
As one of the most important energy sources, natural gas has been more and more widely used in the past few decades [1,2]. Ling et al investigated the adsorption and decomposition mechanism of H2S on different metal-doped α-Fe2O3(001) surfaces. They found that the Fe vacancy surface showed good catalytic activity for the decomposition of H2S, and Zn is beneficial to improve the desulfurization performance [14]. Li et al discussed the adsorption characteristics of NO molecules on oxygen-defective and oxygenfree α-Fe2O3(001) surfaces, and the two surfaces showed opposite electron transfer [15]. There are rare reports on the adsorption of sulfide gases, especially H2S, COS and CH3SH molecules, on the α-Fe2O3 surface using first-principle calculation. We calculated the sulphide gas molecules’ adsorption property on the α-Fe2O3(001) surface by using density functional theory, and investigated the possible binding mechanism of sulfides on the α-Fe2O3 surface. In the formula, ρmolecule/slab, ρ∆slρab=, aρnmdolecρulme/sollaebc−uleρrsleabp−reρsmeonlectultehe total charge density of the systeImn athfteerfoardmsourlap,tiρomno,lectuhle/eslabc,hρasrlagb,eadnednsρimtyolecoulfe trheperseusbensttrathtee btoeftoalrechaadrsgoerpdteionnsi,taynodf tthhee cshyastregme daefntesrityadosfofrrpeetiogna,s tmheolcehcuarlegse, rdeesnpseictytivoeflyt.hMe suullbiksternatcehbaregfoerpeoapdusloartpiotnioann, aalnydsisthise uchseadrgteodeexnamsitiyneofthfreecehgaarsgemtoralencsufelersb, erefospreecatnivdealyft.eMr guallsikaednsocrhpatrigone poonptuhleastiuornfaacnea[l3y8s]i.sAis nuesgeadtitvoeenxuamibneer trheeprcehsaerngtes tarnaneslefectrrboenf,oarnedanadpoasftietirvgeansuamdsboerpintidoincaotnesthaelossusrfoafcele[3c8tr]o. nA
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
