简介:H+-restackednanosheetsandnanoscrollspeeledfromK4Nb6O17displaydifferentstructuresandsurfacecharacters.Thetworestackedsampleswithincreasedsurfaceareashaveanamazingvisible-lightresponseforthephotodegradationofdyes,whichissuperiortocommercialTiO2(P25)andNb2O5.Bycomparison,H+/nanosheetshavearelativelyfasterphotodegradationrateoriginatedfromlargeandsmoothbasalplane.Theworkrevealsthatdyeadsorbedontheunfoldednanosheetscaneffectivelyharvestsunlight.Duetofacilepreparation,low-costandhighphotocatalyticefficiency,H+/nanosheetsandH+/nanoscrollsmightbeusedforthevisiblelight-drivendegradationoforganicdyesasasubstituteforTiO2inindustry.
简介:WithFe(NO3)39H2OandBi(NO3)35H2Oasrawmaterials,differentsillenite-typecompoundsandelementalbismuthwerepreparedbyafacileone-potsolvothermalmethodusingH2O,C2H5OH,(CH2OH)2andC3H8O3assolvents,respec-tively.Thestructure,morphology,elementalcompositionsandpropertiesofsampleswereexaminedbyXRD,SEM,TEM,ICP,XPS,N2adsorptionanddesorption,UV-visDRSandPL.ThephotocatalyticactivitiesofdifferentsampleswereevaluatedbythephotodegradationofRhBundervisible-lightirradiation(λ>400nm),andresultsshowthatBi36Fe2O57preparedusingC2H5OHasthesolventownstheoptimumperformance.Inordertoexplorethereactionmechanism,anadditionalexperimentwasdesignedtoinvestigatethemainactivespeciesduringthephotodegradationprocessviadissolvingdifferenttrappingagentsinthereactionsolutionbeforelightirradiation.TheresultsshowthatsuperoxideradicalanionsplayamajorroleinthissystemsincetheRhBdegradationwassignificantlysuppressedaftertheadditionofbenzoquinone.
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简介:Thenear-ultraviolet(n-UV)excitedblue-emittingSr2MgSi2O7:Eu2+phosphorsareusedforfluorescencelampandtricolorwhiteLEDs.Theeffectofnitrogen-dopedonthestructureofthehostandtheenhancementofphotoluminescenceisexperimentallyinvestigated.Theresultsshowthatastheamountofnitrogen-dopedvariesfrom0to0.6(at.),theluminousintensityisfoundtobeincreasedto169%,andthepartialreplacementofObyNresultsinachangeofthecrystalfieldbymodifyingthesymmetryofthecrystalstructure.Asaresult,withthenitrogen-dopedinsmallamount,theluminousintensity,chromaticitycoordinatesandthecolorpuritycanbeadjustedtoadesiredvalueintheapplications.
简介:ThespinesofpencilandlanceurchinsHeterocentrotusmammillatusandPhyllacanthusimperialiswerestudiedasamodeloflight-weightmaterialwithhighimpactresistance.Thecomplexandvariableskeletonconstruction("stereom")ofbodyandspinesofseaurchinsconsistsofhighlyporousMg-bearingcalciumcarbonate.Thisbasicallybrittlematerialwithpronouncedsingle-crystalcleavagedoesnotfracturebyspontaneouscatastrophicdevicefailurebutbygracefulfailureovertherangeoftensofmillimeterofbulkcompressioninstead.Thiswasobservedinbulkcompressiontestsandbluntindentationexperimentsonregular,infiltratedandlatexcoatedseaurchinspinesegments.MicrostructuralcharacterizationwascarriedoutusingX-raycomputertomography,opticalandscanningelectronmicroscopy.Thebehaviorisinterpretedtoresultfromthehierarchicstructureofseaurchinspinesfromthernacroscaledowntothenanoscale.Guidelinesderivedfromthisstudyseeceramicswithlayeredporosityasapossiblebiomimeticconstructionforappropriateapplications.
简介:Seaurchinspineswerechosenasamodelsystemforbiomimeticceramicsobtainedusingstarch-blendedslipcasting.Porousaluminaceramicswithcap-shapedlayerswithdifferentalternatingporositieswerefoundtohavesuperiorfracturebehaviorunderbulkcompressioncomparedtoceramicswithuniformporosity.Theyfailinacascadingmanner,absorbinghighamountsofenergyduringextendedcompressionpaths.TheporosityvariationinanotherwisesinglephasematerialmimicksthearchitecturalmicrostructuredesignofseaurchinspinesofHeterocentrotusmammillatus,whicharepromisingmodelmaterialsforimpactprotection.
简介:AseriesofCd1-xZnxS/K2La2Ti3O10compositesweresynthesizedviaasimpleco-precipitationmethod.ThepreparedsampleswerecharacterizedbyX-raydiffraction(XRD),scanningelectronmicroscopy(SEM),X-rayenergydispersivespectroscopy(EDX),ultraviolet-visiblediffusereflection(UV-Vis),X-rayphotoelectronspectroscopy(XPS)andphotoluminescence(PL)measurements.ThecompositestructuresconsistedofCd1-xZnxSnanoparticlesevenlydistributedonthesurfaceofK2La2Ti3O10.TheabsorptionedgeofK2La2Ti3O10shiftedtothevisiblelightregionuponintroductionoftheCd1-xZnxSnanoparticles.Thephotocatalyticactivitiesofthecatalystswereevaluatedbyhydrogenproductionundervisiblelightirradiation.ThepreparedCd0.8Zn0.2S(30wt%)/K2La2Ti3O10exhibitedhigherphotocatalyticactivity,evolving6.92mmol/gH2undervisiblelightirradiationfor3h.ThepromotedphotocatalyticactivityofthecompositeswasattributedtothesynergisticeffectbetweenCd1-xZnxSandK2La2Ti3O10,whichresultedinenhancedseparationofphotogeneratedelectronsandholes.