简介:利用密度泛函理论(DensityFunctionalTheory)中的B3LYP方法在6-311+G(d,p)的计算水平上研究了Fe/Fe_2与NO反应的相关微观机理.全参数优化了Fe+NO和Fe_2+NO反应体系在不同重态反应势能面上各驻点的几何结构,并用频率分析法以及内禀反应坐标(IntrinsicReactionCoordinate)方法对过渡态进行了验证,得到了相对应的反应的微观反应路径.用"两态反应"分析反应机理,计算结果表明2个体系的优先选择路径均为低自旋态进入和高自旋态离开反应.通过对2个体系反应活化能的比较,Fe_2+NO体系更易进行.
简介:ThecatalyticactivityofFe/ZSM-5fortheselectivereductionofNOtoN2withmethaneinthepresenceofexcessO2wasstudied.Fe/ZSM-5catalystswithvariousFeloadingswerepreparedbyimpregnationmethod.ItiswellknownthatmethaneisinactivewhenFe/ZSM-5asthecatalystfortheselectivecatalyticreduction(SCR)ofNOwithmethane.However,thispapershowsthatwhenthecontentofFewasabout0.5%,Fe/ZSM-5showedhighercatalyticactivityandselectivityofmethane,andputforwardmeasurableactivationforCH4isanimportantfactorforthereactionofremovalofNOxwithCH4.
简介:Wehavestudiedtheelectronic,bondingandenergeticcharacteristicsoftheFe-Sibinarysystemusingthetight-bondingextendedHuckelmethod.AmongtheFe-Sibinarycompounds,FeSihasthemostsymmetricgeometricarrangementinthecrystalstructure.Italsopossessesthelargestcohesiveenergyperatom.ThiscorrelatestothefactthatFeSiisthemoststablecongruently-meltingcompoundinthebulkphasediagram.Anestimateofinteractionenergiesbetweendifferentatomsisalsogiven.
简介:HighactiveandstablegoldcatalystssupportedoncrystallineFe2O3andCeO2/Fe2O3werepreparedviathedeposition-precipitationmethod.ThecatalystwithaAuloadof1.0%calcinedat180°CshowedaCOconversionof100%at-8.9°C,whileAu/CeO2/Fe2O3convertedCOcompletelyat-16.1°C.Evenhavingbeencalcinedat500°C,Au/Fe2O3stillexhibitedsignificantcatalyticactivity,achievingfullconversionofCOat61.6°C.ThecatalystwithalowAuloadof0.5%couldconvertCOcompletelyatroomtemperatureandkepttheactivityunchangedforatleast150h.N2adsorption-desorptionmeasurementsshowthatthecrystallinesupportspossessedahighspecificsurfaceareaofabout200m2/g.CharacterizationsofX-raydiffractionandtransmissionelectronmicroscopyindicatethatgoldspecieswerehighlydispersedasnanoorsub-nanoparticlesonthesupports.Evenafterthecatalystwascalcinedat500°C,theAuparticlesremainedinanano-sizeofabout6―10nm.X-rayphotoelectronspectrarevealthatthesupportedAuexistedinmetallicstateAu0.ThemodificationofAu/Fe2O3byCeO2provedtobebeneficialtotheinhibitionofcrystallizationofFe2O3andthestabilizationofgoldparticlesindispersedstate,consequentlypromotingcatalyticactivity.
简介:ThepartialoxidationofethanoltohydrogenwasinvestigatedoverNi/Fe/Lacatalystspreparedbytheco-precipitationmethod.TheeffectsofintroductionofLapromoterandthereactiontemperatureonthecatalyticperformancewerestudied.ItwasfoundthattheintroductionofLaintoNi/Fecatalystsishelpfultoincreasetheselectivitytohydrogenandthestabilityofthecatalysts.TheresultsofXRDandXPScharacterizationshowthatthestructureofthecatalystwaschangedduringthereaction.TheexistenceofLaFeO3speciesispossiblythemainreasonoftheincreaseofthecatalyststability.
简介:Inthisletter,Fe2O3UFP(UltrafineParticles)hydrosolandorganosolwithhighthirdorderopticalnonlinearsusceptibility(3)havebeenreportedforthefirsttime.ThesurfacialmodificationofFe2O3UFPwithdodecylbenzenesulfonateions(DBS)canenhancethenonlinearopticalresponsethroughinterfacialconfinementofelectronmotion.Theinvolvedmechanismisdiscussed.
简介:Fe2O3/activecarbon(Fe2O3/AC)nanocompositeswerereadilyfabricatedbypyrolyzingFe3+impregnatedactivecarboninanitrogenatmosphere.Theas-preparedcompositeswerestudiedbyX-raypowderdiffraction(XRD),X-rayphotoelectronspectroscopy(XPS)andtransmissionelectronmicroscopy(TEM).Thecapacitivepropertyofthecompositeswasinvestigatedbycyclicvoltammetry(CV)andgalvanostaticcharge-dischargetest.Physicalcharacterizationsshowthattheγ-Fe2O3finegrainsdispersedintheACwell,withameansizeof21.24nm.Electrochemicaltestsin6mol/LKOHsolutionsindicatethattheas-preparednanocompositesexhibitedimprovedcapacitiveproperties.Thespecificcapacitance(SC)ofFe2O3/ACnanocompositeswasupto188.4F/gthatwasderivedfrombothelectrochemicaldouble-layercapacitanceandpseudo-capacitance,whichwas78%largerthanthatofpristineAC.AsymmetriccapacitorwithFe2O3/ACnanocompositesaselectrodeshowedanexcellentcyclingstability.TheSCwasonlyreducedbyafactorof9.2%after2000cyclesatacurrentdensityof1A/g.
简介:Theopen-frameworkironphosphateFe2^111Fe1.5^11(PO4)3washydrothermallysynthesizedandcharacterizedbyelementalanalysis,IR,EPR,XPSandsinglecrystalX-raydiffractionanalysis.Thetitlecompoundcrystallizedinthetriclinic,spacegroupP-↑1witha=0.64724(4)nm,b=0.79651(6)nm,c=0.94229(5)nm,α=104.447(2)°,β=108.919(4)°,γ=101.741(4)°,V=0.42302(5)nm^3,Z=1andR1(wR2)=0.0307(0.0793).CrystaldatawerecollectedonaRigakuR-AXISRAPIDIPdiffractometerwithMoKα(λ=0.071073nm)at293(2)Kintherangeof2.43°
简介:NanocrystallineNi-Mo-Fealloydepositswereobtainedbyelectrodeposition.ThestructuresofthealloydepositswereanalyzedbyX-raydiffraction(XRD)andX-rayphotoelectronspectroscopy(XPS).TheXRDresultsofnanocrystallineNi-Mo-Fealloydepositshowthatmanydiffractionlinesdisappear,andthatthereisonlyonediffractionpeakat44.0°.TheXPSresultsofnanocrystallineNi-Mo-Fealloydepositsindicatethatthenickel,molybdenumandironofthedepositsexistinmetallicstate,andthatthebindingenergyofthealloyedelementsincreasestosomeextent.ThenanocrystallineNi-Mo-FealloydepositelectrodemayofferbetterelectrocatalyticactivitythanthepolycrystallinenickeleletrodeandthenanocrystallineNi-Moalloyelectrode.TheelectrochemicalimpedancespectrafromthenanocrystallineNi-Mo-Fealloyelectrodeindicatethathydrogenevolutionin30%(m/m)KOHatloweroverpotentialisinaccordancewiththeVolmer-Tafelmechanism,butwiththeVolmer-Heyrovskymechanismathigheroverpotential.
简介:Thenanomaterialsoftenexhibitveryinterestingelectrical,optical,magnetic,andchemicalproperties,whichcannotbeachievedbytheirbulkcounterparts[1-7].Thedevelopmentofuniformnanometersizedparticleshasbeenintensivelypursuedbecauseoftheirtechnologicalandfundamentalscientificimportance[8-15].Itissignificantthatnanostructuredmaterialscanbecontrollablyassembledintotherequiredgeometryontosubstrates,becomingthebasisofthenextgenerationofcomponentsanddevices[16-31].Thedevelopmentofnewmethodsandstrategiesfororganizingthenanoparticlebasicbuildingblocksintothedesiredstructuresisrequired.Superlatticesmadefromthesebuildingblocksgiveustheopportunitytostudynotonlythepropertiesoftheindividualbuildingblocks,butalsocollectiveeffects.Thesuperparamagneticironoxidenanocrystals(NCs)havebeenusedinthefieldsofbio-medicine,ferrofluids,refrigerationsystem,catalysis,particularlyinmagneticresonanceimaging,tissueengineering,anddrugdeliveryapplications[32-42].
简介:Fe2O3solwiththeparticlediameterof3-5nmwasflocculatedbytheadditionofSDS,andtheflocculateformedwasredispersedbythefurtheradditionofthatsurfactant.ThusthesurfactantbilayerwasformedonthesurfaceofFe2O3.Theemulsionpolymerizationofstyrene(St)adsolubilizedonthesurfactantadsorbedbilayerwascarriedoutbyinitiatorpotassiumpersulfate(KPS).TheUV-Visandsurfacephotovoltagespectra(SPS)indicatethattheFe2O3particleswereencapsulatedinpolystyrene(PSt)successfully.
简介:Inthisarticle,nano-scaleAl/Fe2O3compositeswithdifferentmorphologiesweresuccessfullyobtainedbyasimpleelectrospinningtechnique,whichisbasedonasurfactant(polyvinylpyridine,PVP)inamixtureofN,N-dimethylformamide(DMF)and2-propanol.TheelectrospunAl/Fe2O3compositesexhibitedacrystalstructureandphasecompositionbyX-raydiffractionanalysis.ThedifferentmorphologiesoftheAl/Fe2O3compositeswerealsoobservedthroughscanningelectronmicroscopyandtransmissionelectronmicroscopy.Itwasfoundthattherathersimpleelectrospinningmethodusedtopreparethemorphology-controlledAl/Fe2O3compositesmayhavethepotentialforpreparationofpropellants,explosives,andpyrotechnicsinthefuture.
简介:在这研究,新有点磁性、光的Fe3O4/CdTenanocomposites的准备被表明。SuperparamagneticFe3O4nanoparticles被铁、铁的离子的热水的一起沉淀首先综合,与丁氨二酸酸与tetramethylammonium氢氧化物(TMAOH)和化学激活由他们的表面的修正列在后面。修改表面的Fe3O4nanoparticles当时与CdTe量点(QD)是covalently涂的,它与mercaptoacetic酸(MPA)被修改,到通过Fe3O4和carboxyl的表面上的氨基的组的协作的Fe3O4/CdTe磁性、光的nanocomposites在CdTeQD上组织的形式。同样综合的nanocomposites的结构和性质被描绘。nanocomposites与40-50nm,黄绿色的排放特征和房间温度强磁性的一条平均直径拥有了结构,这被显示。荧光和nanocomposites的紫外力的吸收系列显示出CdTeQD与那些作比较的蓝移动。蓝移动的机制被介绍。nanocomposites与8.9emu/g的浸透磁化保留了铁磁性的性质。
简介:为了解河南省内实验室在铝合金化学成分检测领域的整体水平,国家建材质检中心组织实施了铝合金化学成分中Si、Fe含量测定的实验室间比对。本次实验室比对共有20个实验室参加,推荐检测方法为:GB/T7999-2007《铝及铝合金光电直读发射光谱分析方法》,也可采用其他国家标准方法。结果表明:实验室满意结果率为80%,不满意结果率为15%,可疑结果率为5%。参加比对的绝大多数实验室能够准确检测铝合金化学成分含量。