本文選題：原位紅外光譜　切入點：電氧化　出處：《閩南師范大學(xué)》2017年碩士論文

【摘要】：在IS50紅外儀上,成功地構(gòu)建了電化學(xué)原位Fourier變換紅外光譜系統(tǒng),并應(yīng)用電化學(xué)循環(huán)伏安(CV)、原位紅外反射光譜以及時間分辨紅外光譜等技術(shù)研究了堿性介質(zhì)中甘油在Pd電極上的電催化氧化過程,著重跟蹤分析了甘油電氧化過程生成的中間體和產(chǎn)物,考察了甘油濃度對其電氧化機理的影響,為直接甘油燃料電池的產(chǎn)業(yè)化應(yīng)用提供理論指導(dǎo)。得到的主要結(jié)果如下:1、通過對反射附件和紅外光路密封的設(shè)計和調(diào)整,成功地在IS50型紅外儀上構(gòu)建了電化學(xué)原位Fourier變換紅外光譜裝置,實驗效果良好。2、CV的研究結(jié)果表明:正向電位掃描過程中,隨著甘油濃度的增大,甘油氧化峰電流增大,氧化峰電位發(fā)生正移,其電催化氧化的反應(yīng)級數(shù)約為0.1787,且負向電流峰明顯小于正向過程的電流峰,這可能是由于隨著甘油濃度的增大,低電位下甘油解離產(chǎn)生的吸附物種更強烈地吸附在電極表面而引起的。3、堿性介質(zhì)中甘油在Pd電極上只產(chǎn)生橋式吸附態(tài)的CO,而檢測不到線性吸附的CO。由于橋式吸附的CO較線性吸附態(tài)的CO更容易氧化脫附,上述結(jié)果表明:堿性介質(zhì)中甘油在Pd上發(fā)生了解離吸附,其電氧化經(jīng)歷了直接途徑和間接途徑等兩條途徑,但毒化作用相對較小。4、電極電位對甘油電氧化行為及其機理有顯著的影響。1.0M甘油溶液中,低電位下,甘油電氧化產(chǎn)物主要以橋式吸附的CO和甘油醛為主;而高電位下,甘油電氧化產(chǎn)物主要以CO_2、碳酸根和羥基丙酮酸等甘油不完全氧化的產(chǎn)物為主。5、甘油濃度對甘油電氧化行為及其機理也有顯著的影響。甘油濃度對紅外譜峰強度有明顯的影響,濃度越高,譜峰強度越大;吸附態(tài)的CO和產(chǎn)物CO_2的譜峰只出現(xiàn)在高濃度的甘油溶液中,而在低濃度中未檢測到;低濃度溶液中,甘油電氧化產(chǎn)物以碳酸鹽和甘油酸為主,而高濃度溶液中,以CO_2和甘油部分氧化的產(chǎn)物為主。6、高電位下,甘油酸作為中間體可進一步氧化生成羥基丙酮酸;羥基丙酮酸的生成是可能是通過Eley Rideal機理,由中間體甘油酸與吸附態(tài)的OH反應(yīng)而生成的。7、高電位下,甘油電氧化容易形成CO_2產(chǎn)物,其原因可能是由于隨著電位的增大,電極表面吸附態(tài)的OH覆蓋度增大,有利于甘油與多個吸附態(tài)的OH反應(yīng)而引起的。8、高電位下不同濃度甘油的FTIR譜圖,其共同特征是在1585 cm-1附近出現(xiàn)強的譜峰,指示高電位下,各種不同濃度的甘油電氧化均可生成羧酸類化合物。9、電化學(xué)原位時間分辨紅外光譜進一步證實了上述的結(jié)果。10、在實驗條件下,沒有檢測到丙酮酸、丙二酸和丙酮二酸等的生成。11、根據(jù)實驗結(jié)果,在不考慮碳鏈斷裂下,初步提出了堿性介質(zhì)中甘油在鈀電極上可能的電氧化機理。12、由于甘油電氧化過程生成的產(chǎn)物和中間體繁多,在實驗條件下有些物種是否存在,仍無法準確認定,有待今后進一步確認。
[Abstract]:The electrochemical in situ Fourier transform infrared spectroscopy system was successfully constructed on the IS50 infrared spectrometer. Electrochemical cyclic voltammetry (CV), in situ infrared reflectance spectroscopy and time resolved infrared spectroscopy were used to study the electrocatalytic oxidation of glycerol on PD electrode in alkaline medium. The intermediates and products produced during the electrooxidation of glycerol were analyzed, and the effect of glycerol concentration on the electrooxidation mechanism was investigated. To provide theoretical guidance for the industrial application of direct glycerol fuel cells. The main results obtained are as follows: 1. Through the design and adjustment of reflective accessories and infrared light path seals, The electrochemical in situ Fourier transform infrared spectrometer was successfully constructed on the IS50 infrared instrument. The experimental results show that the oxidation peak current of glycerol increases with the increase of glycerol concentration in the process of forward potential scanning. The oxidation peak potential shifted positively, and the reaction order of electrocatalytic oxidation was about 0.1787, and the negative current peak was obviously smaller than the current peak of the forward process, which may be due to the increase of glycerol concentration. The adsorption species produced by glycerol dissociation at low potential are more strongly adsorbed on the electrode surface. In alkaline medium, only bridged CO-adsorbed on PD electrode is produced, but the linear adsorption is not detected. Because of bridge-type adsorption, the adsorptive species of glycerol are adsorbed on the electrode surface more strongly. The oxidation desorption of CO is easier than that of linearly adsorbed CO. The above results show that the dissociation and adsorption of glycerol on PD occur in alkaline medium, and the electrooxidation of glycerol has two pathways, such as direct and indirect pathways, etc. However, the toxic effect is relatively small. 4. The electrode potential has a significant effect on the electrooxidation behavior and mechanism of glycerol. In glycerol solution of 1.0 M, the oxidation products of glycerol are mainly bridge adsorbed CO and glyceraldehyde at low potential, while at high potential, the electrooxidation products are mainly bridged adsorbed CO and glyceraldehyde. The main products of glycerol electrooxidation are CO-2, carbonate and hydroxy pyruvate. The concentration of glycerol also has a significant effect on the electrooxidation behavior and mechanism of glycerol, and the concentration of glycerol has a significant effect on the intensity of infrared spectrum peak. The higher the concentration, the greater the intensity of the peak, the peak of adsorbed CO and product CO_2 only appeared in the high concentration of glycerol solution, but not detected in the low concentration solution, in the low concentration solution, the products of glycerol electrooxidation were mainly carbonate and glyceric acid. In high concentration solution, the product of partial oxidation of CO_2 and glycerol is the main product. At high potential, glyceric acid can be further oxidized to hydroxy pyruvate, and the formation of hydroxy pyruvate may be through the mechanism of Eley / Rideal. At high potential, glycerol is easily oxidized to form CO_2 products, which may be due to the increase of the OH coverage of the adsorbed state on the electrode surface with the increase of potential. In favor of the reaction of glycerol with the OH of several adsorbed states, the FTIR spectra of glycerol with different concentrations at high potential have a strong peak near 1585 cm-1, indicating a strong peak at high potential. Carboxylic acid compounds .9 can be produced by electrooxidation of glycerol at various concentrations. The results are further confirmed by electrochemical in situ time-resolved infrared spectroscopy. No pyruvate was detected under experimental conditions. The formation of malonic acid and pyruvic acid. According to the experimental results, the possible electrooxidation mechanism of glycerol on palladium electrode in alkaline medium was proposed. The existence or not of some species under experimental conditions is still impossible to be identified accurately, and further confirmation is needed in the future.
【學(xué)位授予單位】：閩南師范大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：O657;O643.3

【參考文獻】

相關(guān)期刊論文 前7條

1 饒路;姜艷霞;張斌偉;游樂星;李嶄虹;孫世剛;;乙醇電催化氧化[J];化學(xué)進展;2014年05期

2 倪祖榮;崔曉紅;孫世剛;陳忠;;液相電化學(xué)-核磁共振聯(lián)用技術(shù)及其應(yīng)用[J];光譜學(xué)與光譜分析;2011年01期

3 ;Electrochemical Quartz Crystal Microbalance(EQCM) Characterization of Electrodeposition and Catalytic Activity of Pd-based Electrocatalysts for Ethanol Oxidation[J];Chemical Research in Chinese Universities;2010年03期

4 田中群,任斌,王仲權(quán);表面增強拉曼光譜在電化學(xué)中的應(yīng)用及進展[J];光散射學(xué)報;1998年Z1期

5 田中群,孫世剛,羅瑾,楊勇;現(xiàn)場光譜電化學(xué)研究的新進展[J];物理化學(xué)學(xué)報;1994年09期

6 孫世剛;;固/液界面現(xiàn)場光譜電化學(xué)[J];大學(xué)化學(xué);1993年06期

7 孫世剛;楊東方;田昭武;;丙三醇在Pt電極上吸附和氧化過程的原位FTIR反射光譜研究[J];化學(xué)學(xué)報;1992年06期

相關(guān)博士學(xué)位論文 前1條

1 周志有;原位快速時間分辨顯微FTIRS的建立及其對Pt微電極表面動態(tài)過程的研究[D];廈門大學(xué);2004年

，

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