简介:通过一个简单的水热方法成功地合成出由SnO2纳米片作次级结构的新型花状ZnSnO3-SnO2分级纳米结构。ZnSnO3多面体在生长分级SnO2纳米片的过程中主要起模版作用,制备出的SnO2纳米片的厚度约为25nm。还讨论了ZnSnO3-SnO2样品的形貌随反应时间变化的规律,并且进一步讨论了形成这种分级结构的形成机制。此外,由这种新型ZnSnO3-SnO2纳米结构作敏感材料的气体传感器对乙醇气体具有高灵敏和快响应的特点。ZnSnO3-SnO2纳米片在最佳工作温度270°C时,对50×10-6乙醇气体的灵敏度约为27.8,其响应和恢复时间分别在1s和1.8s内。
简介:Reducingthemanufacturingcostofsolarcellsisnecessarytotheirindustrialproduction.Electrodepositingisaneffective,non-vacuummethodwhichisverysuitableforcuttingthemanufacturingcostofthinfilmsaswellasdevelopingitslarge-scaleindustrialproduction.Inthisstudy,about1-μm-thickCu(In,Ga)Se_2(CIGS)precursorswereelectrodepositedonMo/glasssubstratesinaqueoussolutionutilizingathree-electrodepotentiostaticsystem.Triethanolaminewasusedascomplexingagent,andallparametersofelectrodepositionwerepreciselycontrolled.Afterthat,theelectrodepositedprecursorswereselenizedinaSeatmospherewithdifferentheatingramprates(60and600℃·min~(-1)).High-qualityCIGSfilmswereobtained,andtheircharacteristicswereinvestigatedbyX-rayfluorescence,scanningelectronmicroscopy,energydispersivespectroscopy,X-raydiffraction,Ramanspectraandnear-infrared-visible(NIR-Vis)spectra.Theresultsrevealthattherearemanydifferencesbetweenthepropertiesofthefilmsunderdifferentheatingrates.Finally,CIGSsolarcellswerefabricatedusingafastandaslowheatingrate.Themaximumefficienciesachievedforthefilmsselenizedat60and600℃-min~(-1)are3.15%and0.71%,respectively.
简介:Au/-Al2O3催化剂被免职降水方法为低集中白酒溪流(甲醇,乙醇,iso-propanol和n-propanol)的催化燃烧作好准备。催化剂被X光检查光电子描绘光谱学(XPS),X光检查diffractometry(XRD)和精力散X光检查微分析(版本)技术。XPS结果证明仅仅催化剂的表面上有Au0。XRD模式证明Au高度大概在-Al2O3上被驱散。为有2.0g/m3的集中的甲醇,乙醇,iso-propanol和n-propanol的完全的变换的温度是60,155,170和137?,分别地但是他们完全在60,220,260和217点被使矿物化进CO2和H2O吗?分别地在优化催化剂上。催化剂的活动在130h是稳定的。为催化甲醇消除的动力学跟随了伪--首先订表示为r=0.6528c0+0.084的反应2。明显的激活精力的价值是在反应温度的范围的54.7kJ/mol。
简介:TheslidingfrictionandwearbehaviorsofMg–11Y–5Gd–2Zn–0.5Zr(wt%)alloywereinvestigatedunderoillubricantconditionbypin-on-diskconfigurationwithaconstantslidingdistanceof1,000minthetemperaturerangeof25–200°C.Resultsindicatethatthevolumetricwearratesandaveragefrictioncoefficientsdecreasewiththeincreaseofslidingspeeds,andincreasewiththeincreaseoftesttemperaturebelow150°C.ThehardandthermallystableMg12(Y,Gd)Znphasewithlong-periodstackingorderstructureinthealloypresentssignificantwearresistance.Thewearmechanismbelow100°Cisabrasivewearasaresultofplasticextrusiondeformation.Thecorporateeffectsofsevereabrasive,oxidative,anddelaminatingwearresultinthetribologicalmechanismabove100°C.
简介:在氩气气氛下,将Ag2O与石墨通过机械活化或热还原反应生成Ag,对其等温还原过程的动力学进行研究。结果表明,采用Johnson-Mehl-Avrami模型能合理地解释Ag2O与石墨经机械活化和热还原合成Ag的过程。采用相同的模型来研究机械活化和热还原反应合成Ag的动力学时,机械活化还原过程中的Avrami指数比热还原的要高;热还原和机械活化过程中的晶核长大机制分别是扩散控制和界面控制。
简介:采用直流电弧等离子体法蒸发Mg+5%TiO2的混合物并将其在空气中钝化,制备粉体Mg-TiO2复合储氢材料。利用电感耦合等离子光谱发生仪(ICP)、X射线衍射仪(XRD)、扫描电子显微镜(SEM)表征粉体复合材料的成分、相组成及形貌。采用压力–成分–温度(PCT)和差示扫描量热仪(DSC)对Mg-TiO2样品的吸放氢性能进行研究。由PCT测量结果可知,Mg-TiO2复合粉体中镁的氢化焓和氢化熵分别为-71.5kJ/mol和-130.1J/(K·mol),而粉体的氢化激活能为77.2kJ/mol。结果表明,采用电弧等离子体法在超细镁颗粒中加入TiO2催化剂可显著增强镁的吸放氢动力学性能。
简介:Anewseriesofrareearthcompounds,Y2-xErxMo4O15(x=0.0-2.0),weresynthesizedandtheirstructuresweredeterminedbypowderX-raydiffraction(XRD).RietveldanalysisofXRDpatternsrevealsthatthecompoundsofthisseriescrystallizeinmonoclinicsystemwithspacegroupP21/c.Thelatticeparametersa,b,c,βandtheunitcellvolumeVde-creaselinearlywithincreasingErcontent.Thethermalexpansionpropertiesofthesecompoundswerestudiedunderhigh-temperatureXRD.PositivethermalexpansionsofcompoundsY2-xErxMo4O15arefoundtobeanisotropicalongthethreecrystallographicdirectionswhereaandcaxesexpandwhilebaxiscontractsinthewholetemperaturerange.Byanalysisofdata,theexpansionofweakbandMo2-O14withrisingtemperatureshouldberesponsibleforpositivethermalexpansion.
简介:Withtheassistanceofnonionicsurfactant(OP-10)andsurface-selectivesurfactant(CH3COOH),anataseTiO2waspreparedasananodematerialforlithiumionbatteries.Themorphology,thecrystalstructure,andtheelectrochemicalpropertiesofthepreparedanataseTiO2werecharacterizedbyscanningelectronmicroscopy(SEM),X-raydiffraction(XRD),electrochemicalimpedancespectroscopy(EIS),andgalvanostaticchargeanddischargetest.TheresultshowsthatthepreparedanataseTiO2hashighdischargecapacityandgoodcyclicstability.Themaximumdischargecapacityis313mAh·g-1,andthereisnosignificantcapacitydecayfromthesecondcycle.
简介:通过磁化学熔体反应法在7055(Al-3%B)?Ti反应体系中成功制备TiB2/7055复合材料。利用XRD、OM和SEM等分析检测技术研究复合材料的相组成和微观组织。结果表明,脉冲磁场作用下生成的TiB2颗粒呈多边状或近球形,尺寸小于1μm,均匀分布于基体中。与未施加脉冲磁场的复合材料相比,施加磁场后α(Al)晶粒平均尺寸从20μm减小到约10μm,第二相从连续的网格状分布变为非连续性分布。在磁场作用下,复合材料的抗拉强度从310MPa提高到333MPa,伸长率从7.5%提高到8.0%。此外,与基体相比,在载荷为100N,磨损时间为120min时,复合材料的磨损量从111mg降低到78mg。
简介:ThepermeabilityandstabilityofSm_(0.7)Sr_(0.3)CoO_(3-δ)(SSCO)regardingthespecialrequirementsforcarboncaptureandstorage(CCS)applicationwereinvestigated.PureCO_wasusedasthesweepgasat900°C,leadingtothattheoxygenpermeationfluxdecreasesbyabout34%.SeveralcyclesofchangingthesweepgasbetweenheliumandCO_2indicatethegoodreversibilityofthisdegradation.BothcarbonateformationandadsorptionofCO_2onthemembranesurfaceareresponsibleforthedegradationofthemembraneperformance.ThebetterCO_2resistanceresultsfromthesubstitutionofSmforSrduetothehigheracidityofSm_2O_3(1.278)thanthatofSrO(0.978)andadiscontinuouslayerofcarbonate.