Pb^(2＋)促进乙醇氧化C―C键断裂的在线电化学透射红外光谱研究

On-Line Electrochemical Transmission Infrared Spectroscopic Study of Pb^(2+) Enhanced C―C Bond Breaking in the Ethanol Oxidation Reaction

近些年来,直接乙醇燃料电池(DEFC)凭借其能量密度高、绿色环保、毒性低等诸多优点受到了广泛关注,相关的机理研究重点关注的是如何高效地催化乙醇C―C键的断裂。本文通过建立电化学在线透射红外方法,对碱性体系下Pb^(2+)对Pt催化乙醇氧化反应(EOR)的影响进行了研究。结果发现,在不同温度、催化剂载量和电势条件下,Pb^(2+)的加入都有利于Pt催化EOR活性的提高,同时能够提高乙醇氧化电流的稳定性。我们利用电化学在线透射红外光谱(ETIRS)方法对Pt催化EOR的反应产物进行了检测,发现Pb^(2+)存在时产物碳酸根的电流效率明显高于Pb^(2+)不存在时的结果,这一结果说明了Pb^(2+)存在下Pt催化EOR中C―C键断裂比例的提高可能是反应活性提高的重要原因。

Direct ethanol fuel cell（DEFC） has received much attention because of its high energy density,environmental friendliness,and low toxicity.Mechanism studies have focused on improving the breaking ratio of the C―C bond during the ethanol oxidation reaction（EOR）.We establish an on-line electrochemical transmission infrared spectroscopic（ETIRS） method for electrochemical reactions.The new method is applied to study the effect of the addition of Pb^（2＋）on the EOR catalyzed by Pt in an alkaline solution.We perform a series of electrochemical experiments at different temperatures,different catalyst loadings,and different potentials.The addition of Pb^（2＋）is shown to improve the reaction rate of EOR in each experiment.Additionally,the anodic current becomes more stable with Pb^（2＋）addition in the solutions.By using ETIRS,the products of the EOR are detected.The results show that the current efficiency of the carbonate is obviously higher in the presence of Pb^（2＋）than that without Pb^（2＋）.This indicates that Pb^（2＋）may improve the breaking ratio of the C―C bond during the EOR,which results in an increase of the EOR current.