在金銀電極上電解二氧化碳制備一氧化碳的研究
發(fā)布時間：2018-08-26 19:38
【摘要】：C02是主要的溫室氣體,也是自然界最重要和最豐富的一種碳源。將C02轉(zhuǎn)化為有用化學(xué)品,減少化石燃料的使用量,是實現(xiàn)C02減排的重要途徑之一。本論文采用新型隔膜電解池,分別在KHCO3水溶液、四丁基高氯酸銨(TBAP)/二甲基亞砜(DMSO)溶液和四丁基高氯酸銨(TBAP)/碳酸丙烯酯(PC)溶液中,研究了C02在Au、Ag電極上的電化學(xué)還原反應(yīng),分析了CO2在Ag電極上發(fā)生電還原反應(yīng)的電極失活機理,探索了CO2在非水體系電解液中的電還原行為。主要研究內(nèi)容如下：(1)利用循環(huán)伏安、塔菲爾曲線、恒電位電解和氣相色譜等方法,研究了C02在Au、Ag電極上發(fā)生電還原反應(yīng)的動力學(xué)特征。結(jié)果表明,在KHCO3水溶液中,CO2可以發(fā)生電還原反應(yīng),生成CO。在Au、Ag電極上CO2電還原反應(yīng)的交換電流密度分別為4.014×10-4A/cm2、3.011×10-4A/cm2,平衡電位分別為-0.720V、-0.934V,最高電流效率分別可達84%和67%。(2)利用線性掃描、塔菲爾曲線、恒電位電解、掃描電鏡、電化學(xué)阻抗譜和X射線光電子能譜(XPS)等方法,分析了CO2在Ag電極上發(fā)生電還原反應(yīng)的電極失活機理。結(jié)果表明,在CO2電還原反應(yīng)過程中,一些有害物質(zhì)附著在電極表面上,導(dǎo)致生成CO的平衡電位負(fù)移,交換電流密度變小,電荷轉(zhuǎn)移電阻增大,電流效率和電流密度迅速降低。X射線光電子能譜(XPS)分析結(jié)果表明,陰極表面的附著物為石墨碳和微量Zn。(3)利用循環(huán)伏安曲線、恒電位電解曲線、電化學(xué)阻抗譜和氣相色譜分析等方法,研究了CO2在非水體系電解液中的電還原行為。結(jié)果表明,在TBAP/DMSO溶液和TBAP/PC溶液中,CO2電還原反應(yīng)的電流密度分別只有3.2mA/cm2和4.5mA/cm2, Ag電極的失活并不嚴(yán)重。電化學(xué)阻抗譜分析結(jié)果表明,上述兩種電解液的電極過程均由電荷傳遞和擴散過程共同控制。電還原反應(yīng)剛開始時,C02在TBAP/DMSO溶液和TBAP/PC溶液中電還原生成CO的電流效率分別可達到87%和89%。在長時間的電還原過程中,Ag電極一直保持著很高的催化活性,2h的電解后電流效率仍分別為81.3%和83%。
[Abstract]:CO2 is the main greenhouse gas and the most important and abundant carbon source in nature. Converting CO2 into useful chemicals and reducing the use of fossil fuels is one of the important ways to reduce CO2 emissions. In this paper, the electrochemical reduction reaction of C02 on Au,Ag electrode was studied in KHCO3 aqueous solution, tetraDing Ji ammonium perchlorate (TBAP) / dimethyl sulfoxide (DMSO) solution and (TBAP) / propylene carbonate (PC) solution, respectively. The electroreduction mechanism of CO2 on Ag electrode was analyzed, and the electroreduction behavior of CO2 in non-aqueous electrolyte was explored. The main contents are as follows: (1) using cyclic voltammetry, Taffer curve, potentiostatic electrolysis and gas chromatography, the kinetic characteristics of electrochemical reduction of CO2 on Au,Ag electrode were studied. The results show that CO _ 2 can be electroreduced to form CO. in KHCO3 aqueous solution. The exchange current density of CO2 electroreduction reaction on Au,Ag electrode is 4.014 脳 10 ~ (-4) A / cm ~ (-2) and the equilibrium potential is -0.720 V / cm ~ (-0.934) V, respectively. The maximum current efficiency is 84% and 67%, respectively. (2) by linear scanning, Taffel curve, potentiostatic electrolysis, scanning electron microscope, Electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS) were used to analyze the deactivation mechanism of electroreduction reaction of CO2 on Ag electrode. The results show that during the electroreduction of CO2, some harmful substances are attached to the electrode surface, which leads to the negative shift of the equilibrium potential for the formation of CO, the decrease of the exchange current density and the increase of the charge transfer resistance. The results of X-ray photoelectron spectroscopy (XPS) analysis show that the attached materials on the cathode surface are graphite carbon and trace Zn. (3) using cyclic voltammetry curve and constant potential electrolysis curve. Electrochemical impedance spectroscopy (EIS) and gas chromatographic analysis (GC) were used to study the electroreduction behavior of CO2 in non-aqueous electrolyte. The results show that the current density of CO _ 2 electroreduction in TBAP/DMSO solution and TBAP/PC solution is only 3.2mA/cm2 and 4.5 Ma / cm ~ 2, respectively. The deactivation of Ag electrode is not serious. The results of electrochemical impedance spectroscopy show that the electrode process of the two kinds of electrolytes is controlled by charge transfer and diffusion process. At the beginning of the electroreduction reaction, the current efficiency of electroreduction of C02 to CO in TBAP/DMSO solution and TBAP/PC solution was up to 87% and 89%, respectively. During the long time electroreduction, the electrolysis current efficiency of Ag electrode was 81.3% and 833%, respectively, after electrolysis with high catalytic activity for 2 h.
【學(xué)位授予單位】：昆明理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TQ127.12
本文編號：2205955
[Abstract]:CO2 is the main greenhouse gas and the most important and abundant carbon source in nature. Converting CO2 into useful chemicals and reducing the use of fossil fuels is one of the important ways to reduce CO2 emissions. In this paper, the electrochemical reduction reaction of C02 on Au,Ag electrode was studied in KHCO3 aqueous solution, tetraDing Ji ammonium perchlorate (TBAP) / dimethyl sulfoxide (DMSO) solution and (TBAP) / propylene carbonate (PC) solution, respectively. The electroreduction mechanism of CO2 on Ag electrode was analyzed, and the electroreduction behavior of CO2 in non-aqueous electrolyte was explored. The main contents are as follows: (1) using cyclic voltammetry, Taffer curve, potentiostatic electrolysis and gas chromatography, the kinetic characteristics of electrochemical reduction of CO2 on Au,Ag electrode were studied. The results show that CO _ 2 can be electroreduced to form CO. in KHCO3 aqueous solution. The exchange current density of CO2 electroreduction reaction on Au,Ag electrode is 4.014 脳 10 ~ (-4) A / cm ~ (-2) and the equilibrium potential is -0.720 V / cm ~ (-0.934) V, respectively. The maximum current efficiency is 84% and 67%, respectively. (2) by linear scanning, Taffel curve, potentiostatic electrolysis, scanning electron microscope, Electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS) were used to analyze the deactivation mechanism of electroreduction reaction of CO2 on Ag electrode. The results show that during the electroreduction of CO2, some harmful substances are attached to the electrode surface, which leads to the negative shift of the equilibrium potential for the formation of CO, the decrease of the exchange current density and the increase of the charge transfer resistance. The results of X-ray photoelectron spectroscopy (XPS) analysis show that the attached materials on the cathode surface are graphite carbon and trace Zn. (3) using cyclic voltammetry curve and constant potential electrolysis curve. Electrochemical impedance spectroscopy (EIS) and gas chromatographic analysis (GC) were used to study the electroreduction behavior of CO2 in non-aqueous electrolyte. The results show that the current density of CO _ 2 electroreduction in TBAP/DMSO solution and TBAP/PC solution is only 3.2mA/cm2 and 4.5 Ma / cm ~ 2, respectively. The deactivation of Ag electrode is not serious. The results of electrochemical impedance spectroscopy show that the electrode process of the two kinds of electrolytes is controlled by charge transfer and diffusion process. At the beginning of the electroreduction reaction, the current efficiency of electroreduction of C02 to CO in TBAP/DMSO solution and TBAP/PC solution was up to 87% and 89%, respectively. During the long time electroreduction, the electrolysis current efficiency of Ag electrode was 81.3% and 833%, respectively, after electrolysis with high catalytic activity for 2 h.
【學(xué)位授予單位】：昆明理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TQ127.12
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