Electrochemical In-situ FTIR System Construction And Its Application In The Electrooxidation Of Glycerol

With the help of successful experiences of xiamen university,we successfully constructed the in situ electrochemical Fourier transform infrared spectroscopy in the IS50 type infrared device manufactured by thermo Nicolet company in our laboratory.Glycerol electric-oxidation process in alkaline medium on the Pd electrode were studied by using the electrochemical cyclic voltammograms,in situ FTIRs and time-resolved FTIRs techniques.By analyzing the intermediates and products generated in glycerol oxidation process and glycerol concentration on its oxidation mechanism,we try to further reveal its electrical oxidation mechanism from the molecular level and provide theoretical guidance for industrialization of the direct glycerol fuel cell.The main results are as follows:1.By adjusting the reflection accessories and sealing infrared light road,we successfully constructed the electrochemical in situ Fourier transform infrared spectrum on IS50 type and the experimental effect is good.2.The CV results show that in the positive potential scan process,with the increase of glycerol concentration,glycerol oxidation peak current increases,the oxidation peak potential is positive-shift and its reaction series is about 0.1787,the positive peak current is significantly greater than the negative current peak and it is may be due to the adsorption species more strongly adsorbed on the electrode surface at low with the increase of glycerol concentration.3.Bridge-bonded CO may be generated from dissociative adsorption of glycerol in alkaline medium on the Pd electrode,but linear-bonded CO do not.Because of the Bridge-bonded CO be easily oxidized,the results show that glycerol in alkaline medium at Pd electrode understand from the dissociative adsorption and the electrooxidation process has experienced two way: direct way and indirect way,but poison effect is relatively small.4.Electrode potential have a significant impact.on glycerol electrooxidation behavior and its mechanism.In 1.0 M glycerol solution,at low potential,glycerol electrooxidation products are mainly Bridge-bonded CO and glyceraldehyde;at high potential,glycerol electrooxidation products are primarily CO2,carbonate and hydroxypyruvic acid(glycerol incomplete oxidation products).5.Glycerol concentration also have a significant impact on glycerol electrooxidation behavior and its mechanism.Glycerol concentrations have obviously effects on infrared spectral peak intensity;spectral peak of Bridge-bonded CO and CO2 appear only in high concentration glycerol solution,but not be detected in low concentration;products of glycerol electrooxidation are mainly carbonate and glyceric acid in low concentration,and CO2 and partial oxidation products in high concentration.6.At high potential,glyceric acid as intermediates can be further oxidized to generate hydroxylpyruvic acid;glyceric acid may react with adsorption state of OH to generate hydroxylpyruvate through Eley Rideal – mechanism.7.At high potential,glycerol electrooxidation tends to form CO2 product,which may be due to,with the increase of potential electrode,the increase of surface coverage of adsorption state OH and glycerol is easy to react with multiple adsorption state of OH.8.At high potential,in different glycerol concentrations,the FTIR spectra have common characteristic at around 1585 cm-1 with a strong spectral peak,indicating glycerol electrooxidation in different glycerol concentrations at high potential produce carboxylic acid compounds.9.Electrochemical in situ time-resolved FTIR spectra further confirm the above results.10.Under the experimental condition,no malonic acid,pyruvic acid and malonic acid were detected.11.According to the experimental results,the possible mechanism of glycerol electrooxidation in alkaline medium at palladium electrode has been put forward without considering the carbon chain broken.12.As many products and intermediates may be generated from glycerol electric-oxidation process,under the experimental conditions,some species still cannot be accurately determined,remains to be further confirmed.