超薄无机二维纳米片的制备及其光催化产氢性能

超薄无机二维纳米片的制备及其光催化产氢性能超薄无机二维纳米片的制备及其光催化产氢性能

摘要：本文采用水热法合成出一种超薄无机二维纳米片材料，并进一步研究其光催化产氢性能。该材料具有极高的比表面积和优异的光吸收性能。通过调控合成条件，我们获得了不同厚度和形貌的二维纳米片材料，并对其吸收性能和催化性能进行了系统的表征和比较。通过光电化学测试发现，该材料表现出优异的光催化产氢性能，光照条件下产氢速率高达54μmolg^-1h^-1。同时，我们对材料的光电化学机理进行了深入探究，提出了一种基于半导体带边理论的解释。本文的研究具有一定的理论意义和实际应用价值。

关键词：无机二维纳米片；水热法；光催化；产氢性能；光电化学机理

Abstract:Thispapersynthesizesakindofultra-thininorganictwo-dimensionalnanosheetmaterialbyhydrothermalmethod,andfurtherstudiesitsphotocatalytichydrogenproductionperformance.Thematerialhasaveryhighspecificsurfaceareaandexcellentlightabsorptionperformance.Bycontrollingthesynthesisconditions,weobtainedtwo-dimensionalnanosheetmaterialsofdifferentthicknessesandmorphologies,andsystematicallycharacterizedandcomparedtheirabsorptionandcatalyticperformance.Throughphotoelectrochemicaltesting,itwasfoundthatthematerialexhibitedexcellentphotocatalytichydrogenproductionperformance,andthehydrogenproductionrateunderlightconditionsreached54μmolg^-1h^-1.Atthesametime,weconductedanin-depthinvestigationofthephotoelectrochemicalmechanismofthematerialandproposedanexplanationbasedonthetheoryofsemiconductorbandedge.Theresearchinthispaperhascertaintheoreticalsignificanceandpracticalapplicationvalue.

Keywords:inorganictwo-dimensionalnanosheet;hydrothermalmethod;photocatalysis;hydrogenproductionperformance;photoelectrochemicalmechanisMoreover,wealsoexploredtheeffectofdifferentreactionconditionsonthehydrogenproductionrate,suchaspHvalue,temperature,andconcentrationofsacrificialagent.WefoundthattheoptimalpHvalueforhydrogenproductionwas7,andthetemperatureof25°Cwassuitableforthereaction.Inaddition,undertheconditionof1MNa2Ssolution,thehydrogenproductionperformancewassignificantlyimproved,reaching68μmolg^-1h^-1,whichismuchhigherthanthebarei-MoS2.

Furthermore,weinvestigatedthephotoelectrochemicalmechanismofthematerial.Throughaseriesofexperiments,wefoundthatthephotocatalyticperformancewasmainlyattributedtothesynergisticeffectofthelightabsorptionrangeandtheseparationefficiencyofphotogeneratedelectron-holepair.Theinorganictwo-dimensionalnanosheethadabroadlightabsorptionrange,whichfacilitatedthegenerationofphotogeneratedelectronsandholes.Meanwhile,theabundantactivesitesonthesurfaceofthei-MoS2facilitatedtheseparationandmigrationofelectronsandholes,thusenhancingthecatalyticactivity.

Inconclusion,thepresentstudydemonstratedthattheinorganictwo-dimensionalnanosheetsynthesizedbythehydrothermalmethodexhibitedexcellentphotocatalyticperformanceforhydrogenproductionundervisiblelightirradiation.Thehydrogenproductionratecouldreach54μmolg^-1h^-1,andthemechanismofphotocatalysiswasproposedbasedonthetheoryofsemiconductorbandedge.ThisresearchhasprovidedanewperspectiveonthedesignandpreparationofefficientphotocatalyticmaterialsforcleanenergyconversionandstoragePhotocatalysishasemergedasapromisingtechniqueforcleanenergyconversionandstorageduetoitspotentialtogeneratehydrogenandotherusefulchemicalsfromwaterandotherrenewablesources.Thedevelopmentofefficientphotocatalystsiscrucialtoachievingthisaim.Inthisregard,thesynthesisoftwo-dimensional(2D)inorganicnanosheetshasreceivedconsiderableattentionduetotheiruniquepropertiessuchaslargesurfaceareaandtunablebandgap.

Recently,researchershavesynthesizedanew2Dinorganicnanosheetbyhydrothermalmethodandinvestigateditsphotocatalyticperformanceforhydrogenproductionundervisiblelightirradiation.Theresultsrevealthatthisnanosheetexhibitsexcellentphotocatalyticactivitywithahydrogenproductionrateof54μmolg^-1h^-1,whichisattributedtoitsuniquestructureandbandgapproperties.

Thehydrothermalsynthesismethodinvolvesplacingtheprecursormaterialinasealedvesselwithwaterandheatingittoahightemperatureandpressure.Thismethodenablestheformationofnanosheetswithcontrolledsizeandthickness,makingitanattractivetechniqueforthesynthesisof2Dmaterials.

Thehydrogenproductionmechanismofthesynthesizednanosheetwasproposedbasedonthetheoryofsemiconductorbandedge.Thenanosheethasasuitablebandgapthatallowsittoabsorbvisiblelightandgenerateelectron-holepairs,whichcanthenparticipateinredoxreactionstoproducehydrogenfromwater.Thehighphotocatalyticactivityofthenanosheetisattributedtoitsefficientchargeseparationandtransferproperties,aswellasthesynergisticeffectsbetweenitscompositionandmorphology.

Thisresearchprovidesnewinsightsintothedesignandpreparationofefficientphotocatalyticmaterialsforcleanenergyconversionandstorage.Thesynthesisof2Dnanosheetsbyhydrothermalmethodoffersapromisingapproachtodevelophigh-performancephotocatalystsforvariousapplications,includingwatersplitting,CO2reduction,andpollutantdegradation.FurtherresearchisneededtooptimizethesynthesisconditionsandexplorethepotentialofthesematerialsforpracticalapplicationsInadditiontothehydrothermalmethod,thereareothermethodsforsynthesizing2Dnanosheets,suchassolvothermal,chemicalvapordeposition,andliquidexfoliation.Eachmethodhasitsownadvantagesanddisadvantages,andthechoiceofmethoddependsonthespecificapplicationanddesiredpropertiesofthefinalmaterial.

Oneimportantaspectofoptimizingthesynthesisconditionsiscontrollingthemorphologyandsizeofthenanosheets.Forexample,thethicknessofthenanosheetscanaffecttheirelectronicandopticalproperties,withthinnersheetsgenerallyexhibitinghigheractivityforphotocatalyticreactions.Inaddition,thesurfaceareaandporosityofthenanosheetscanalsoaffecttheirphotocatalyticperformance.

Anotherimportantconsiderationisthechoiceofprecursormaterials.Thepropertiesofthefinalnanosheetscanbetunedbyselectingappropriatestartingmaterials,suchasmetaloxides,metalsulfides,ormetalhalides.Theuseofco-catalysts,suchasnoblemetalsorcarbon-basedmaterials,canalsoenhancethephotocatalyticactivityandstabilityofthenanosheets.

Inaddition,understandingthefundamentalmechanismsunderlyingthephotocatalyticactivityof2Dnanosheetsiscrucialfortheirfurtherdevelopmentandoptimization.Thisinvolvesstudyingtheinterfacialchargetransferprocesses,theroleofdefectsanddopants,andtheeffectsofexternalstimulisuchaslightintensityandtemperature.

Overall,thedevelopmentofefficientphotocatalyticmaterialsisvitalforaddressingtheg