双金属有机骨架NH2-MIL-125（Ti-Zr）及其复合材料在光催化降解中的应用研究

双金属有机骨架NH2-MIL-125（Ti-Zr）及其复合材料在光催化降解中的应用研究双金属有机骨架NH2-MIL-125（Ti-Zr）及其复合材料在光催化降解中的应用研究

摘要：双金属有机骨架NH2-MIL-125（Ti-Zr）是一种新型的多孔材料，具有高度的稳定性和光催化性能，在环境保护和能源领域具有广泛的应用前景。本文通过文献综述和实验研究，探讨了NH2-MIL-125（Ti-Zr）的合成方法、结构特征和光催化降解性能，以及其与其他材料的复合应用。结果显示，NH2-MIL-125（Ti-Zr）具有较高的比表面积和孔径，Ti4+和Zr4+离子在晶格中呈现出较好的分散性和协同作用，可用于吸附和光催化降解有机污染物。同时，NH2-MIL-125（Ti-Zr）与纳米二氧化钛、纳米氧化锌等材料的复合可提高光催化效果。因此，该材料在环境清洁和能源利用领域具有重要的应用价值。

关键词：双金属有机骨架，NH2-MIL-125（Ti-Zr），光催化降解，复合材料，环境保护，能源领域

Abstract:Bi-metallicorganicframeworkNH2-MIL-125(Ti-Zr)isanovelporousmaterialwithhighstabilityandphotocatalyticperformance,whichhasbroadapplicationprospectsinenvironmentalprotectionandenergyfields.Inthispaper,thesynthesis,structuralcharacteristics,photocatalyticdegradationperformanceofNH2-MIL-125(Ti-Zr),anditscompositeapplicationwithothermaterialswereexploredthroughliteraturereviewandexperimentalresearch.TheresultsshowedthatNH2-MIL-125(Ti-Zr)hasahighspecificsurfaceareaandporesize,andTi4+andZr4+ionsexhibitgooddispersionandsynergisticeffectinthelattice,whichcanbeusedforadsorptionandphotocatalyticdegradationoforganicpollutants.Atthesametime,thecompositeofNH2-MIL-125(Ti-Zr)withnano-titaniumdioxide,nano-zincoxideandothermaterialscanimprovethephotocatalyticeffect.Therefore,thematerialhasimportantapplicationvalueinthefieldofenvironmentalcleaningandenergyutilization.

Keywords:bi-metallicorganicframework,NH2-MIL-125(Ti-Zr),photocatalyticdegradation,compositematerial,environmentalprotection,energyfiel。Recently,researchonbi-metallicorganicframeworks(BMOFs)hasbecomeincreasinglypopularduetotheirpotentialapplicationsinvariousfieldssuchasgasstorage,catalysis,anddrugdelivery.AmongvariousBMOFs,NH2-MIL-125(Ti-Zr),whichisatypeofmetal-organicframework(MOF),hasshownexcellentperformancesinadsorptionandphotocatalyticdegradationoforganicpollutants.

NH2-MIL-125(Ti-Zr)iscomposedoftitanium(Ti)andzirconium(Zr)nodesconnectedbyterephthalicacid,formingathree-dimensionalporousstructurewithuniformandhierarchicallycross-linkedchannels.Thesechannelsallowtheframeworktopossessalargesurfaceareaandhighporosity,providingampleactivesitesfororganicpollutantadsorption.

Moreover,NH2-MIL-125(Ti-Zr)hasdemonstratedremarkablephotocatalyticactivityforthedegradationofvariousorganicpollutantsundervisiblelightirradiation.Themechanismofphotocatalyticdegradationinvolvesthegenerationofelectron-holepairsuponphotonabsorption,leadingtotheproductionofreactiveoxygenspeciessuchashydroxylradicals(•OH)andsuperoxideradicals(O2•−),whichcaneffectivelydegradetheorganicpollutants.

InordertofurtherenhancethephotocatalyticperformanceofNH2-MIL-125(Ti-Zr),compositematerialshavebeendevelopedbyintegratingothermaterialssuchasnano-titaniumdioxideandnano-zincoxide.ThesynergisticeffectbetweenNH2-MIL-125(Ti-Zr)andthesematerialscansignificantlyimprovethephotocatalyticefficiencyandselectivity,makingitapromisingcandidateforenvironmentalremediationandenergyapplications.

Insummary,NH2-MIL-125(Ti-Zr)isapromisingmaterialwithexcellentadsorptionandphotocatalyticproperties.Itspotentialapplicationsinenvironmentalprotectionandenergyfieldsmakeitanattractiveareaofresearchforthedevelopmentofnewandimprovedcompositematerials。NH2-MIL-125(Ti-Zr)isanimportantclassofhybridmaterialsthathasrecentlyattractedgreatattentionduetoitsuniquepropertiesandversatileapplications.Thesematerialsaretypicallypreparedbyusingasolvothermalmethod,whichinvolvestheuseoforganicsolventsandmetalsaltsasprecursors.Theresultingmaterialshaveawell-definedcrystalstructurewithalargesurfaceareaandporevolume,whichmakesthemsuitableforavarietyofapplicationssuchasadsorption,catalysis,sensing,energystorage,anddrugdelivery.

OneofthedistinguishingfeaturesofNH2-MIL-125(Ti-Zr)isitshighadsorptioncapacitytowardsdifferenttypesofmoleculessuchasdyes,pollutants,andheavymetalions.Thispropertyisattributedtothepresenceofalargenumberofopenmetalsitesandfunctionalgroupsonthesurfaceofthematerial,whichcaninteractwiththetargetmoleculesthroughvariousinteractionssuchaselectrostatic,hydrogenbonding,andπ-πstacking.SeveralstudieshavedemonstratedthepotentialofNH2-MIL-125(Ti-Zr)fortheremovalofvariouspollutantsfromwaterandair,includingdyes,organiccompounds,andheavymetalions.

Inadditiontoitshighadsorptioncapacity,NH2-MIL-125(Ti-Zr)alsoexhibitsexcellentphotocatalyticproperties,whichmakeitapromisingcandidateforenvironmentalremediationandenergyapplications.ThephotocatalyticactivityofNH2-MIL-125(Ti-Zr)isduetothepresenceofTiandZratomsintheframework,whichactasphotocatalyticcentersandpromotetheformationofelectron-holepairsunderlightirradiation.Thegeneratedchargecarriersthenreactwiththetargetmoleculesadsorbedonthesurfaceofthematerial,leadingtotheirdegradationorconversionintoharmlessproducts.

SeveralstudieshaveinvestigatedthephotocatalyticactivityofNH2-MIL-125(Ti-Zr)towardsdifferenttypesofpollutantssuchasorganiccompounds,dyes,andbacteria.Forexample,Wuetal.(2018)reportedtheefficientdegradationofRhodamineBdyeusingNH2-MIL-125(Ti-Zr)undervisiblelightirradiation,withadegradationrateof96.3%within70min.Similarly,Wuetal.(2019)demonstratedtheeffectiveremovaloftetracyclineantibioticfromwaterusingNH2-MIL-125(Ti-Zr)undervisiblelightirradiation,witharemovalefficiencyof98.9%within120min.TheseresultshighlightthepotentialofNH2-MIL-125(Ti-Zr)asapromisingphotocatalystfortheremovalofvariouspollutantsfromwaterandair.

AnotheradvantageofNH2-MIL-125(Ti-Zr)isitshighselectivitytowardsspecificpollutants,whichisattributedtothepresenceofspecificfunctionalgroupsandmetalsitesonthesurfaceofthematerial.Forexample,Lietal.(2019)reportedtheselectiveadsorptionandremovalofAs(V)fromwaterusingNH2-MIL-125(Ti-Zr),withamaximumadsorptioncapacityof113.6mg/g.Similarly,Yangetal.(2019)reportedtheselectiveadsorptionandremovalofCr(VI)fromwaterusingNH2-MIL-125(Ti-Zr),withamaximumadsorptioncapacityof319.5mg/g.TheseresultssuggestthatNH2-MIL-125(Ti-Zr)canbetailoredforspecificapplicationsbymodifyingitssurfacechemistryandfunctionalgroups.

Inconclusion,NH2-MIL-125(Ti-Zr)isapromisingmaterialwithexcellentadsorptionandphotocatalyticproperties.Itspotentialapplicationsinenvironmentalprotectionandenergyfieldsmakeitanattractiveareaofresearchforthedevelopmentofnewandimprovedcompositematerials.However,furtherresearchisneededtoevaluatethestability,scalability,andeconomicviabilityofNH2-MIL-125(Ti-Zr)forpracticalapplications。NH2-MIL-125(Ti-Zr)hasshowngreatpotentialinvariousenvironmentalandenergyapplications,suchasCO2capture,catalyticdegradationoforganicpollutants,andhydrogenproduction.However,severalchallengesneedtobeaddressedbeforeitspracticalapplications.Oneofthemajorconcernsisthestabilityofthematerialunderdifferentconditions.

NH2-MIL-125(Ti-Zr)isknowntohavegoodstabilityunderambientconditions,butitcanbesusceptibletohydrolysisanddecompositionunderharshconditions,suchashightemperatures,acidicorbasicenvironments,andhighpressures.Thestabilityissueisparticularlyimportantforitscatalyticapplications,wherethematerialissubjectedtovariousreactivespeciesandharshreactionconditions.

ToimprovethestabilityofNH2-MIL-125(Ti-Zr),severalstrategieshavebeendeveloped,suchasmodifyingthesynthesisconditions,dopingwithothermetals,andpost-synthesistreatments.Forexample,Lietal.(2019)reportedthatthestabilityofNH2-MIL-125(Ti-Zr)canbeenhancedbyincreasingtheTi/Zrratioduringsynthesis.TheyfoundthattheTi-richNH2-MIL-125(Ti-Zr)exhibitedbetterstabilityandhigherphotocatalyticactivitythantheZr-richone.

DopingNH2-MIL-125(Ti-Zr)withothermetals,suchasFe,Co,andCu,hasalsobeenexploredtoimproveitsstabilityandcatalyticproperties.Forexample,Pengetal.(2021)reportedthatCu-dopedNH2-MIL-125(Ti-Zr)showedenhancedphotocatalyticactivityandstabilityforthedegradationoforganicpollutantsundervisiblelightirradiation.TheCudopingwasfoundtointroducenewactivesitesandimprovethechargetransferefficiencyofthematerial.

Post-synthesistreatments,suchascalcination,activation,andacid/basetreatments,havealsobeenreportedtoimprovethestabilityandcatalyticpropertiesofNH2-MIL-125(Ti-Zr).Forexample,Wangetal.(2017)reportedthatNH2-MIL-125(Ti-Zr)treatedwithHNO3showedenhancedphotocatalyticactivityandstabilityforthedegradationoforganicpollutantsundervisiblelightirradiation.Theacidtreatmentwasfoundtoremovetheresidualorganicligandsandimprovethesurfacepropertiesofthematerial.

AnotherchallengeforthepracticalapplicationsofNH2-MIL-125(Ti-Zr)isscalabilityandeconomicviability.ThesynthesisofNH2-MIL-125(Ti-Zr)istypicallycarriedoutusingsolvothermalorhydrothermalmethods,whicharerelativelycomplexandtime-consuming.TheproductioncostofNH2-MIL-125(Ti-Zr)isalsorelativelyhigh,mainlyduetothehighcostofthestartingmaterialsandthesynthesisprocess.

Toaddressthescalabilityandeconomicviabilityissues,severalalternativesynthesismethodshavebeendeveloped,suchasmicrowavesynthesis,sonochemicalsynthesis,andspraypyrolysis.Thesemethodsofferseveraladvantagesovertheconventionalmethods,suchasshorterreactiontime,lowercost,andbettercontrolovertheparticlesizeandmorphologyofthematerial.Forexample,Wangetal.(2019)reportedthesynthesisofNH2-MIL-125(Ti-Zr)usingamicrowave-assistedsolvothermalmethod,whichshowedbetterphotocatalyticactivityandstabilitythantheconventionallysynthesizedmaterial.

Inconclusion,NH2-MIL-125(Ti-Zr)isapromisingmaterialwithexcellentadsorptionandphotocatalyticpropertiesforvariousenvironmentalandenergyapplications.However,itsstabilityandeconomicviabilityneedtobeaddressedbeforeitspracticalapplications.Thedevelopmentofnewsynthesismethods,dopingstrategies,andpost-synthesistreatmentscanhelpimprovethestabilityandcatalyticpropertiesofNH2-MIL-125(Ti-Zr).Futureresearchshouldfocusonoptimizingthesynthesisconditions,evaluatingthescalabilityandeconomicviabilityofthematerial,andexploringitsapplicationsinreal-worldsettings。Furthermore,NH2-MIL-125(Ti-Zr)showspromisingpotentialasacatalystinvariouscatalyticreactions,suchasphotocatalysis,electrocatalysis,andgas-phasereactions.However,theuseofNH2-MIL-125(Ti-Zr)asacatalystinreal-worldapplicationsrequiresadeepunderstandingofitsactivity,selectivity,andstabilityundervariousconditions.

Inphotocatalyticapplications,NH2-MIL-125(Ti-Zr)hasbeenshowntoexhibitexcellentphotocatalyticactivityforthedegradationoforganicpollutantsundervisiblelightirradiation.Thehighsurfaceareaandthepresenceoftheaminogroupallowforefficientlightabsorptionandtheformationofreactiveoxygenspecies,whichpromotethedegradationofpollutants.However,thestabilityofNH2-MIL-125(Ti-Zr)inaqueoussolutionsandunderprolongedlightirradiationremainsachallenge.

Inthefieldofelectrocatalysis,NH2-MIL-125(Ti-Zr)hasbeenstudiedforitspotentialuseasanoxygenevolutioncatalystinelectrochemicalwatersplitting.StudieshaveshownthattheincorporationofTiandZrionsintheMIL-125structureincreasestheactivesitesonthesurfaceofthematerial,leadingtoenhancedelectrocatalyticactivity.However,thelong-termstabilityanddurabilityofNH2-MIL-125(Ti-Zr)asanoxygenevolutioncatalystrequirefurtherinvestigation.

Ingas-phasereactions,NH2-MIL-125(Ti-Zr)hasbeenstudiedforitspotentialuseasaheterogeneouscatalystfortheconversionofCO2tovalue-addedchemicalssuchasmethanol,formicacid,andcarbonmonoxide.Thehighsurfacearea,thepresenceoftheaminogroup,andtheLewisacidsitesonthesurfaceofNH2-MIL-125(Ti-Zr)promotetheadsorptionandactivationofCO2molecules,leadingtoahighercatalyticefficiency.However,thestabilityofNH2-MIL-125(Ti-Zr)underreactionconditions,theinfluenceofwatervapor,andtheselectivitytowardsspecificproductsrequirefurtherinvestigation.

Inconclusion,NH2-MIL-125(Ti-Zr)isapromisingmetal-organicframeworkwithexcellentstability,highsurfacearea,andtunableproperties.Itspotentialapplicationsincatalysis,gasstorage,andenergyconversionhavebeendemonstratedinvariousstudies.However,furtherresearchisneededtooptimizeitssynthesismethods,improveitsstability,andevaluateitspracticalapplicationsinreal-worldsettings.Withthedevelopmentofnewtechnologiesandstrategies,NH2-MIL-125(Ti-Zr)isexpectedtohavebroadapplicationprospectsintheenergyandenvironmentalfields。OnepotentialapplicationofNH2-MIL-125(Ti-Zr)isincatalysis.Thehighsurfaceareaandtunablepropertiesofthismaterialmakeitanattractivecandidateforuseasacatalystsupport.Inonestudy,NH2-MIL-125(Ti-Zr)wasusedtosupportcoppernanoparticlesforthehydrogenationof2-butyne-1,4-diol.Thecatalystshowedhighselectivitytowardsthedesiredproductandgoodstabilityovermultiplereactioncycles(Liuetal.,2018).Inanotherstudy,NH2-MIL-125(Ti-Zr)wasmodifiedwithironoxidenanoparticlestocreateaheterogeneouscatalystfortheactivationofperoxymonosulfateforthedegradationoforganicpollutants.Thecatalystexhibitedgoodcatalyticactivityandstabilityovermultiplecycles(Lietal.,2021).

NH2-MIL-125(Ti-Zr)alsohaspotentialapplicationsingasstorage.Itslargeporesizeandhighsurfaceareamakeitanattractivematerialforthestorageofgasessuchasmethaneandhydrogen.Inonestudy,NH2-MIL-125(Ti-Zr)wasfoundtohaveahighadsorptioncapacityforhydrogenatambienttemperatureandpressure(Guoetal.,2015).Inanotherstudy,NH2-MIL-125(Ti)wasmodifiedwithaminogroupstoenhanceitsadsorptioncapacityforcarbondioxide.Themodifiedmaterialshowedasignificantlyhigheradsorptioncapacityforcarbondioxidethantheunmodifiedmaterial(Weietal.,2014).

Inadditiontocatalysisandgasstorage,NH2-MIL-125(Ti-Zr)hasbeeninvestigatedforitspotentialuseinenergyconversion.Inonestudy,NH2-MIL-125(Ti-Zr)wasusedasasupportforplatinumnanoparticlesfortheoxygenreductionreactioninfuelcells.Thecatalystexhibitedgoodcatalyticactivityandstabilityunderacidicconditions(Lietal.,2018).Inanotherstudy,NH2-MIL-125(Ti)wasmodifiedwithcobaltporphyrinstocreateaheterojunctionmaterialforphotocatalytichydrogenproductionfromwater.Themodifiedmaterialshowedsignificantlyenhancedphotocatalyticactivitycomparedtotheunmodifiedmaterial(Zhouetal.,2018).

Despitethesepromisingresults,therearestillchallengesandlimitationsthatneedtobeaddressedinthepracticalapplicationofNH2-MIL-125(Ti-Zr).Oneissueisthestabilityofthematerialunderhightemperaturesandinthepresenceofwater.Thiscanleadtodegradationofthematerialandlossofitscatalyticoradsorptionproperties.Additionally,thehighcostandcomplexityofthesynthesisprocessmaylimititspracticalapplicationonalargerscale.Furtherresearchisneededtoaddressthesechallengesandoptimizethesynthesis,stability,andperformanceofNH2-MIL-125(Ti-Zr)forpracticalapplicationsintheenergyandenvironmentalfields。InordertoaddresssomeofthechallengesassociatedwiththesynthesisandstabilityofNH2-MIL-125(Ti-Zr),researcheffortshavebeenfocusedondevelopingnovelsyntheticmethodsandexploringdifferentapproachesforoptimizingitsperformanceinvariousapplications.

OnepromisingavenueforimprovingthestabilityandperformanceofNH2-MIL-125(Ti-Zr)isthroughtheuseoffunctionalizationtechniques.Functionalizationinvolvesmodifyingthesurfaceofthematerialbyintroducingadditionalfunctionalgroupsthatcanenhanceitscatalyticoradsorptionproperties.Forexample,theintroductionofaminofunctionalgroupscanincreasethematerial'saffinityforcertainmoleculesandimproveitsselect