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1、物理化学学报(WuliHuaxueXuebao)MarchActaPhys.-Chim.Sin.2015,31(3),489-497489[Article]doi:10.3866/PKU.WHXB201501221www.whxb.pku.edu.cn基于新球型微观结构模型模拟PEMFC催化层1,2,*22张洁婧王宇新许莉(1吉林农业大学生命科学学院,长春130118;2天津大学化工学院,化学工程联合国家重点实验室,天津300072)摘要:建立了一个新球型催化层微观结构模型,并基于此模型对质子交换膜燃料电池(PEMFC)性能进行了模拟.该模型中假设催化层由Pt/C颗粒和离子聚合物-孔混合相组成
2、.假设Pt/C颗粒为球形结构,其直径符合正态分布,用不同直径的球来表示随机分散在电极中的Pt/C颗粒.计算了催化层内的传递和电化学反应,研究了质子和氧气及电化学反应速率在电极厚度方向上的分布,并且通过对比氧气浓度、过电位和电化学反应速率的分布、极化曲线及催化剂利用率等证明了适当的电极厚度与Pt/C颗粒粒径有利于提高电池性能.关键词:超薄电极;球型微观模型;Pt/C颗粒粒径;电极厚度;催化剂利用率中图分类号:O646SimulationofSphere-MicrostructureModeloftheCatalystLayerinaPEMFC1,2,*22ZHANGJie-JingWANGYu-
3、XinXULi(1SchoolofLifeSciences,JilinAgriculturalUniversity,Changchun130118,P.R.China;2StateKeyLaboratoryofChemicalEngineering,SchoolofChemicalEngineeringandTechnology,TianjinUniversity,Tianjin300072,P.R.China)Abstract:Thecatalystlayerinaproton-exchange-membranefuelcell(PEMFC)wassimulatedbasedonaspher
4、e-microstructuremodelthatconsistedofPt/Cparticlesandamixedionomer-porephase.Pt/Cparticleswererandomlydistributedinthemodelandweretreatedassphereswithanormaldistributionoftheirsizeassumed.Transportandelectrochemicalreactionsinthemodelcatalystlayerwerecalculated.Thevariationofoxygenlevel,overpotential
5、,reactionrate,andcellcurrentthroughthecatalystlayerwasdiscussedinrelationtochangesinelectrodethicknessandPt/Cparticlesize.Thecorrespondingpolarizationcurveswerealsoanalyzed.Throughthisanalysis,optimalvaluesforelectrodethicknessandparticlesizewereachieved.KeyWords:Ultrathinelectrode;Spheremicrostruct
6、uremodel;Pt/Cparticlesize;Electrodethickness;Catalystutilization1引言膜电极(MEA)是质子交换膜燃料电池(PEMFC)质子交换膜燃料电池因其具有高效、低污染、的核心部件,由聚合物电解质膜及其两侧的电极催起动快等优点,而被认为是最有应用前景的电源之化层组成.电极催化层一般由随机分布的Pt/C颗一.但是,性能差、成本高等缺点阻碍了其商业化进粒、离子聚合物和孔组成.Pt/C颗粒、离子聚合物和程.若要提高电池性能并降低成本,势必要优化电孔分别给电子、质子及反应物提供传递通路.电化池的关键部件.学反应仅发生在三条通路同时具备的反应活性位R
7、eceived:November4,2014;Revised:January22,2015;PublishedonWeb:January22,2015.∗Correspondingauthor.Email:zjjx124@163.com;Tel:+86-431-84533360-8023.TheprojectwassupportedbytheNationalNaturalScienceFounda
