基于电化学原位红外光谱方法研究PtAu甲醇电催化氧化机理

Research of Methanol Electrocatalytic Oxidation Mechanism of PtAu by Electrochemical In-Situ FTIRS

研究电化学反应过程的中间物种和反应机理对于构建催化剂表界面组成,结构和性能的构效关系具有重要意义。衰减全反射红外光谱方法由于隐失波的红外吸收特性,对于表面吸附态物种具有较高的灵敏度,广泛应用于表界面反应机理研究。基于这一方法,本工作对PtAu的甲醇电催化氧化的机理进行研究。通过对比反应中主要中间物种(HCOOad和COad)的浓度变化,我们发现甲醇氧化的主要途径是非CO途径;通过分峰拟合的方法对反应中CO的种类和浓度进行分峰和统计,发现反应中存在多种吸附态CO,且随着反应的进行存在CO迁移现象。利用CO作为探针分子进行毒化实验,证明反应过程中OH主要的吸附位点是Pt。结合分峰拟合方法对反应过程中多种水进行结构区分和浓度分析,确认弱氢键水参与甲醇电催化氧化反应。

It is important to study the intermediate species and reaction mechanism in the electrochemical reaction process to construct the structure-activity relationship between the surface composition and performance of the catalyst.Attenuated total reflection infrared spectroscopy(ATR-IR)is widely used to study of surface reaction mechanism due to its high sensitivity to surface adsorbed species by infrared absorption characteristics of Hidden wave.Based on this method,the electrocatalytic oxidation mechanism of PtAu for methanol was studied.By comparing the concentration changes of the main intermediate species(HCOOad and COad),we found that the main route of methanol oxidation is non-CO pathway.Through the peak fitting method,the species and concentration of CO in the reaction were distinguished and analyzed,and it was found that there were many kinds of adsorbed CO in the reaction,and CO migration existed with the reaction.It was found that Pt was the main adsorption site of OH by CO poisoning experiment.The structure and concentration of several kinds of water in the reaction process were analyzed by peak splitting fitting method,the results show that the weak hydrogen bond water is involved in the electrocatalytic oxidation of methanol.