基于石墨烯电极材料的微生物燃料电池(英文)

496June2015|Vol.58No.6©ScienceChinaPressandSpringer-VerlagBerlinHeidelberg2015REVIEWSCIENCECHINAMaterialsGraphene-basedelectrodematerialsformicrobialfuelcellsSuqinCi1,PingweiCai1,ZhenhaiWen1,2*andJinghongLi3*Microbialfuelcells(MFCs)areenvironmentallyfriendlytech-nologycapableofconvertingchemicalenergystoredinwaste-watersdirectlyintoelectricalenergybyusingmicroorganismsasbiocatalysts.However,theoveralllowpowerdensityoftheMFCandthehighcostofitscomponentsaretwomajorbarriersforitscommercialization.Amongallthefactors,theelectrodes(cathodeandanode)materialsplaythesignificantroleinaf-fectingtheperformanceofMFCs.Recently,theperformanceofMFCshasbeenimprovedbyusinggraphene-basedelectrodesthataremoreconductiveandmechanicallystablewithlargersurfaceareaandhigherelectrocatalyticactivitycomparedtotheconventionalcarbonmaterials.Thispaperprovidesanover-viewofrecentresearchprogressingraphene-basedmaterialsaselectrodesforMFCs,whichwillbethepromisingcandidatesfordevelopingMFCsandotherbioelectrochemicalsystemstoachievesustainablewater/wastewatertreatmentandbioenergyproduction.INTRODUCTIONInthepastdecade,microbialfuelcells(MFCs)havebeenemergingasoneofthepromisingalternativetechnologiesforharvestingrenewableenergythroughwastewatertreat-ment[1–3].Thetraditionaltwochamber-MFCstypicallyhaveananodeandacathodeseparatedbyaprotonex-changemembraneinatwochambersetup(Fig.1).Whenorganiccompounds(e.g.,organicwastesinwastewater)areinfusedintotheanodechamber,electrochemicallyac-tivebacteriaoxidizethesubstrateswithproducingprotonsandelectrons.Theprotonspassthroughtheprotonex-changemembranetothecathode.Electronsaretransferredthroughanexternalcircuitfromtheanodetothecathode,drivinganexternalloadandreducingtheelectronacceptor(e.g.,oxygen)atthecathode.Astheelectrodesarethesitesforelectrontransfer,excellentelectricalconductivityisthefavoritepropertiesforthepotentialelectrodematerial.Be-sidesthis,adesirableanodematerialshouldbebiocompat-1KeyLaboratoryofJiangxiProvinceforPersistentPollutantsControlandResourcesRecycle,NanchangHangkongUniversity,Nanchang330063,China2FujianProvincialKeyLaboratoryofNanomaterials,FujianInstituteofResearchontheStructureofMatter,ChineseAcademyofSciences,Fuzhou350002,China3DepartmentofChemistry,TsinghuaUniversity,Beijing10086,China*Correspondingauthors(emails:[e-mail](WenZ);[e-mail](LiJ))iblesothatbacteriaintroducedintothesystemwillformabiofilmontheanode,whileafavorablecathodematerialshouldhaveahighlyelectrocatalyticactivitytowardoxi-dants(e.g.,oxygen)reductionreaction.However,highcostofcathodecatalystsandlowchargetransferefficiencyofelectrodesrestrictthedevelopmentofMFCtechnology[4].Toaddresstheseissues,avarietyofmaterialsandtheirmodifications,includingcarbon/graphitematerials,car-bonnanotubes(CNTs),nanostructuredmaterialsandnon-preciousmetals,havebeenstudied,asreviewedindetailelsewhere[1,5].WhilesometraditionalmaterialshaveshowncertainpromiseinMFCs,theirapplicationsarestilllimitedbytheirintrinsicissues,suchaslowspe-cificsurfacearea,lowconductivity,poorbiocompatibility,and/orcomplicatedsynthesisprocedures.Forinstance,thesynthesisofmultiwallCNTs(MWCNTs)isnormallycar-riedoutatahighertemperature(500°C)inthepresenceofmetalcatalystusingthechemicalvapourdeposition(CVD)technique[6].ThepresenceofmetalcatalystintheMWCNTs-basedcathodecanalsohavenegativeeffectsontheperformanceofMFC.Graphene,asanewlydevelopedmaterial,canbesynthesizedatroomtemperatureusingsimplesolutionchemistryatamuchlowercostthanthatofMWCNTs,duringwhichtoxicmetalcatalystsarenotused.Inthisprospect,grapheneisadesiredalternativetoMWCNTsforapplicationintheMFCs[7].Sofar,graphenebasedmaterialshavebeenextensivelyinvestigatedandenvisagedaspotentialelectrodematerialsforlithiumionbatteries,supercapacitors,biosensors,pho-tovoltaiccells,andcatalysisduetoitsattractiveproperties,includinghighsurfacearea(theoreticalvalue2630m2g−1),highconductivity,andeasysynthesisprocess[8,9].RecentstudiesshowthemaximumpowerdensityoftheMFCshasbeensignificantlyimprovedbyusingthegrapheneasthecatalystsupportduetothebetterdispersionofthemetalmater.scichina.comlink.springer.comPublishedonline19June2015|doi:10.1007/s40843-015-0061-2SciChinaMater2015,58:496–509June2015|Vol.58No.6497©ScienceChinaPressandSpringer-VerlagBerlinHeidelberg2015SCIENCECHINAMaterialsREVIEWcatalystsonthegraphenesurface[10–12].Inadditiontobeinganexcellentcatalystsupport,thepotentialofusinggraphene-basedcathode/anodeelectrodeinMFCshasalsobeendemonstratedinsomestudies[13–19].Allstudiesre-vealedthegreatpotentialofusinggraphenetoimprovetheelectrodeperformanceinMFCs.ThisreviewsummarizestherecentdevelopmentsusinggrapheneaseithercatalystsorsupportsofelectrodeforMFCs,whichconsistsoftwomajorsections:1)theprog-ressregardinggrapheneasthecathodecatalystsofMFCs,and2)themodificationofgrapheneastheanodeelectrodeforimprovingMFCperformance.GRAPHENE-BASEDCATHODEMATERIALSLikeconventionalfuelcells,electronsproducedontheanodesideofMFCspassthroughanexternalelectriccir-cuitandthenareconsumedonthecathodeside(Fig.1).Therefore,aproperele