简介：Variousmesoporouschromiaaluminacatalystswerepreparedbyfivedifferentmethodsbasedonametal-organicframeworkMIL-101andtheircatalyticperformancesoverisobutanedehydrogenationwereinvestigated.ThehighlydispersedchromiumspecieswereproducedoncatalystKCrAl-I1withlargestspecificsurfaceareaof198m2g-1preparedwithaluminiumisopropoxide(Al(i-OC3H7)3)byultrasonicimpregnationmethod.However,thecatalystKCrAl-I2synthesizedbystirringimpregnationpossessedcrystallineα-Cr2O3phase,whichwaspoorlydispersed.TwotypesofCr-richandAl-richCrxAl2-xO3solidsolutions,designatedasCrAl-IandCrAl-IIphase,wereformedoverthecatalystsKCrAl-I3(preparedbyAl(i-OC3H7)3withnitricacidregulation),KCrAl-C4(preparedbyaluminiumchloridehexahydrate)andKCrAl-N5(preparedbyaluminiumnitratenonahydrate).CatalyticevaluationresultsrevealedthatKCrAl-I1exhibitedthehighisobutaneconversionduetoitshighlydispersedchromiumspecies.However,KCrAl-I3,KCrAl-C4andKCrAl-N5showedthehigherisobuteneselectivity(95.2%-96.4%)onaccountoftheformationofchromiaaluminasolidsolutionsinthecatalysts.Moreover,thesolidsolutionoverthechromiaaluminacatalystscouldgreatlysuppressthecokeformation.

简介：Publicparksprovidemanybenefitstothecommunityastherepresentativesofgreenarea.Theallocationofpublicplacesplaysanextremelyimportantroleinthedailylivesofinhabitantsespeciallyforrecreationalusethatcouldenhancethequalityoflifeofresidentsinthevicinity.Tounderstandparkusers'behaviorisoneofthemostimportantprerequisitesforassessingtheparticipationinpublicservicefromtheparkusers'pointofview.Thepatternofparkutilizationonlocationandactivityselectionareimportantelementsinbehavioralstudy,whilethepublicparkstopographmayalsoinfluencethetypicaluser'sbehavior.Questionnairesurveyonparkutilizationwasusedtoinvestigatetheinteractionbetweenactivityinvolvementandrecreationallocationwiththeuseoflineardiscriminantanalysis(LDA)model.Thestudyfoundthatpublicparkusers'behaviorisinfluencednotonlybysocialcharacteristicsbutalsobytherecreationalactivitiesandtheirspecificlocationcharacteristics.Wefoundthatabout45percentofparkvisitorsarelocalresidentslivingwithinaradiusof3kmpreferredtraveltoparksneartheirresidentialarea.Thisimpliesthatlocationselectionbehavioriscorrelatedwithtraveldistance,traveltimeandtravelcost.Visitfrequenciesandonsiteexpendituresreflecttherecreationbehaviorfordifferenttypeofactivities.Theoverallinformationcanbeusefullyappliedbydecisionmakerstolaunchappropriatepublicpolicyinconsistencewiththeusefulresultsofthisstudy.

简介：Anovelvisiblelightactivephoto-catalystnamedCHC/C-PVA/TiO2,thecompositeoftitaniumdioxide（TiO2）withconjugatedderivativeofpolyvinylalcohol（C-PVA）loadedonacordieritehoneycombceramic（CHC）substrate,wasfabricatedbycombiningthesynthesisofTiO2sol,preparationofC-PVAviathermallytreatingpolyvinylalcohol,andimmobilizationofTiO2solandC-PVAonCHC.BydetectingthechangeofUV–visabsorptionspectraofthemodelorganicpollutant（methylorange（MO））inthepresenceofthecompositeundervisiblelightirradiation,thephoto-catalyticactivitywasevaluatedandtheresultsshowthattheCHC/C-PVA/TiO2compositehasanenhancedphoto-catalyticactivitywhencomparedtotheCHC/TiO2composite.Besides,theCHC/C-PVA/TiO2showsagoodphoto-catalyticstabilityafterthefourthcycles.Thestructureanalysesbyscanningelectronmicroscope（SEM）andenergydispersiveX-rayspectroscopy（EDS）showthecoexistenceofC-PVAandTiO2ontheCHCandthecracksonthesurfaceofCHC/C-PVA/TiO2.Resultofultraviolet-visiblediffusereflectionspectroscopy（UV–visDRS）revealsthattheCHC/C-PVA/TiO2canabsorbbothultravioletandvisiblelightwhileresultofX-rayphotoelectronspectroscopy（XPS）indicatestheexistenceofC,OandTielementsintheCHC/C-PVA/TiO2.ThetypicalstructuresaswellastheopticalcharacteristicsoftheCHC/C-PVA/TiO2areresponsiblefortheenhancementinthephoto-catalyticactivity.

简介：PalladiumcatalystsaresupportedonTiO2,ZrO2,Al2O3,Zr0.5Al0.5O1.75andTiO2-Zr0.5Al0.5O1.75preparedbyco-precipitationmethod,respectively.CatalyticactivitiesformethaneandCOoxidationareevaluatedinagasmixturethatsimulatedtheexhaustfromlean-burnnaturalgasvehicles(NGVs).Pd/TiO2-Zr0.5Al0.5O1.75performsthebestcatalyticactivityamongthetestedfivecatalysts.ForCH4,thelight-offtemperature(T50)is254℃,andthecompleteconversiontemperature(T90)is280℃;forCO,T50is84℃,andT90was96℃.Varioustechniques,includingN2adsorption-desorption,X-raydiffraction(XRD),H2-temperature-programmedreduction(H2-TPR),X-rayphotoelectronspectroscopy(XPS),andscanningelectronmicroscopy(SEM)areemployedtocharacterizetheeffectofsupportsonthephysicochemicalpropertiesofpreparedcatalysts.N2adsorption-desorptionandSEMshowthatTiO2-Zr0.5Al0.5O1.75expressesuniformnano-particlesandlargemeso-porediametersof26nm.H2-TPRandXRDindicatethatPdOiswelldispersedonthesupportsandstronglyinteractedwitheachother.TheresultsofXPSshowthattheelectrondensityaroundPdOandtheproportionofactiveoxygenonTiO2-Zr0.5Al0.5O1.75aremaximaamongthefivesupports.