Studies On Chemically Modified Electrodes And Electrocatalysis Combined With NMR Characterization

As a branch of chemistry,electrochemistry mainly explores the connection between electric and chemical action,and studies the phenomenon of the interface of electronic conductive phase and chemical phase.Electrochemical analysis technology is based on electrical signals to explore the connection between the material change and the charge transfer.Thus,this analysis method cannot reveal the mechanism of electrode surface and the electrochemical reaction from the microcosmic angle.As a popular detection means,the nuclear magnetic resonance(NMR)technology can deeply analyze the material structure inside without destroying the tested object.This technology is also able to provide the information about the molecular structure and molecular dynamics of the analyzed matter.Nowadays,the nuclear magnetic resonance technology has become a conventional method to analyze the molecular structure and explore the characterization of physical and chemical properties.In recent years,coupling electrochemistry to various research means has widely reported in literature.As one of the tool to explore the molecular structure,the nuclear magnetic resonance technology has gradually been applied in the electrochemistry field.Different from the electrochemical analysis method,the NMR spectroscopy can directly get the information including the material structure,composition and molecular orientation.What is more,the NMR technology has the advantages of rich structure information,high resolution,sensitivity about environmental detection and accurate and quantitative.The nuclear magnetic resonance technology has good prospects in the field of electrochemistry,and can be applied in a great many of researches of theory and practice.Thus,the combination of electrochemistry and the NMR technology can enhance the exploration of the mechanism of chemical reaction process.The purpose of this study is to explore the influence of modified electrodes in the electrochemical reaction system by the electrochemical-nuclear magnetic resonance technology.First,we make a brief introduce of the chemical modified electrodes and preparation methods.Then,we use electrochemical polymerization in order to prepare the polyaniline modified glassy carbon electrode.The polyaniline modified electrode is used to electrolyze the hydroquinone and the catechol.The signals of electrolytic products are assigned and compared by the EC-NMR analysis method,and we obtain the conclusion that the polyaniline modified electrode has obvious electrocatalytic activity for two kinds of phenols.Then,the electrochemical properties of hydroquinone with different catalyst modified electrodes were studied by the EC-NMR technology,and we also compare the catalytic performance of different catalysts.The individual catalyst modified electrodes,as we know,have the different electrochemical properties.We use the electrochemistry technology to explore the electrochemical behavior of the electron transfer on the electrode surface.Meanwhile,by the EC-NMR technology,we can obtain the information of the influence of the change of the material composition during the electrochemical reaction could be obtained.In addition,the pure shift 1H NMR spectroscopy is introduced briefly.After that,we chose the mixed alcohols in the fuel cell as the research object,and carried out a preliminary exploration for the subsequent mixed alcohols electrocatalysis.Then,we carry out the NMR experiments of ZS sequence in the mixed alcohol system.After analyzing the mixed alcohol spectrum,we can come to the conclusion that the pure chemical shift technology is an excellent way to avoid the overlapping of the peaks caused by the J coupling,which can simplify the complex hydrogen spectrum and improve the observing resolution of the spectrum.