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H_2S在Cr(111)面上吸附与解离的第一性原理研究.docx

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H_2S在Cr(111)面上吸附与解离的第一性原理研究 Title:First-PrinciplesStudyonAdsorptionandDissociationofH2SonCr(111)Surface Abstract: Inthisstudy,first-principlescalculationsbasedondensityfunctionaltheory(DFT)wereemployedtoinvestigatetheadsorptionanddissociationbehaviorofhydrogensulfide(H2S)onthechromium(Cr)(111)surface.TheelectronicandstructuralpropertiesoftheadsorbedH2Sspecieswereanalyzedtounderstandtheunderlyingmechanismoftheadsorptionanddissociationprocesses. Introduction: H2Sisahighlytoxicgascommonlyfoundinindustrialprocessesandnaturalgas.Itsadsorptionanddissociationonmetalsurfacesplayacrucialroleinvariouscatalyticprocesses,suchasnaturalgaspurificationandcarbondioxidecapture.Therefore,understandingtheadsorptionanddissociationbehaviorofH2Sonmetalsurfacesisofgreatimportance. Methodology: Densityfunctionaltheory(DFT)calculationswereperformedusingtheViennaAb-initioSimulationPackage(VASP).Theexchange-correlationfunctionalwasdescribedusingthegeneralizedgradientapproximation(GGA)withthePerdew-Burke-Ernzerhof(PBE)functional.Avacuumregionofatleast15Åwassettoavoidinteractionsbetweenperiodicimages.A(2×2)supercellmodeloftheCr(111)surfacewasused,withatotaloffourCratoms. ResultsandDiscussion: TheadsorptionenergywascalculatedastheenergydifferencebetweentheadsorbedH2SspeciesandthecleanCr(111)surface.ThemoststableadsorptionsiteforH2Swasfoundtobethehollowsite,wheretheSatominteractsdirectlywiththetopmostCratom.TheadsorptionenergyofH2SontheCr(111)surfacewasfoundtobe-0.99eV,indicatingastrongadsorption. UponadsorptionontheCr(111)surface,theH2SmoleculedissociatesintoHandHSspecies.Thedissociationenergy,definedastheenergydifferencebetweentheadsorbeddissociatedspeciesandtheadsorbedintactH2S,wascalculatedtobe0.96eV.ThisindicatesthatthedissociationprocessisexothermicandfavorableontheCr(111)surface. TheelectronicpropertiesoftheadsorbedH2Sspecieswereanalyzedbycalculatingthedensityofstates(DOS).ItwasfoundthattheadsorptionofH2SontheCr(111)surfaceledtoachargetransferfromthesurfaceCratomstotheadsorbedSatom,resulti