资源描述：
《pd催化甲醇裂解制氢的反应机理》由会员上传分享，免费在线阅读，更多相关内容在教育资源-天天文库。
1、物理化学学报(WuliHuaxueXuebao)876ActaPhys.鄄Chim.Sin.,2009,25(5)：876-882May[Article]www.whxb.pku.edu.cnPd催化甲醇裂解制氢的反应机理*倪哲明毛江洪潘国祥胥倩李小年(浙江工业大学化学工程与材料学院,杭州310032)摘要：基于密度泛函理论(DFT),研究了甲醇在Pd(111)面上首先发生O—H键断裂的反应历程(CH3OH(s)寅CH3O(s)+H(s)寅CH2O(s)+2H(s)寅CHO(s)+3H(s)寅CO(s)+4H(s)).优化了裂解过程中各反应物、中间体、过
2、渡态和产物的几何构型,获得了反应路径上各物种的吸附能及各基元反应的活化能数据.另外,对甲醇发生C—O键断裂生成CH3(s)和OH(s)的分解过程也进行了模拟计算.计算结果表明,O—H键的断裂(活化能为103.1kJ·mol-1)比C—O键的断裂(活化能为249.3kJ·mol-1)更容易;甲醇在Pd(111)面上裂解的主要反应历程是:甲醇首先发生O—H键的断裂,生成甲氧基中间体(CH3O(s)),然后甲氧基中间体再逐步脱氢生成CO(s)和H(s).甲醇发生O—H键断裂的活化能为103.1kJ·mol-1,甲氧基上脱氢的活化能为106.7kJ·mol-1,
3、两者均有可能是整个裂解反应的速控步骤.关键词：甲醇裂解;反应机理;密度泛函理论;过渡态中图分类号：O641MechanismofPalladium鄄CatalyzedMethanolDecompositionforHydrogenProduction*NIZhe鄄MingMAOJiang鄄HongPANGuo鄄XiangXUQianLIXiao鄄Nian(CollegeofChemicalEngineeringandMaterialsScience,ZhejiangUniversityofTechnology,Hangzhou310032,P.R.Chi
4、na)Abstract：Thereactionpathwayofmethanoldecomposition(CH3OH(s)寅CH3O(s)+H(s)寅CH2O(s)+2H(s)寅CHO(s)+3H(s)寅CO(s)+4H(s))onPd(111)surfaceswasstudiedusingdensityfunctionaltheory(DFT).Geometriesofreactants,intermediates,transitionstatesandproductswerecalculated.Adsorptionenergiesofpossib
5、lespeciesandactivationenergybarriersofpossibleelementaryreactionsinvolvedinthemechanismwereobtainedinthiswork.Inaddition,westudiedthereactionmechanismforC—Obondscissioninmethanoldecomposition,whichledtotheformationofCH3(s)andOH(s).ResultsshowthatO—Hbondscission(withanactivationen
6、ergybarrierof103.1kJ·mol-1)requireslessenergythanC—Obondscission(withanactivationenergybarrierof249.3kJ·mol-1).ThemajorreactionpathwayonPd(111)surfacesinvolvesO—HbondscissioninCH3OHandthenafurtherdecompositionoftheresultantmethoxyintermediatetoCO(s)andH(s)viasequentialhydrogenabs
7、tractionfromCH3O(s).O—Hbondscissioninmethanolandhydrogenabstractionfromthemethoxygrouparepossiblerate鄄determiningstepsforthisdecompositionwithactivationenergybarriersof103.1and106.7kJ·mol-1,respectively.KeyWords：Methanoldecomposition;Reactionmechanism;Densityfunctionaltheory;Tran
8、sitionstate[1,2]进入21世纪之后,人类面临着能源与环境两已经成为
