电化学活化铂催化剂用于燃烧反应

NULL论文
论文详情
The subject of this thesis is the study of electrochemical promotion of catalysis (EPOC) also called non-Faradaic electrochemical modification of catalytic activity (NEMCA). In EPOC, the application of small current or potential on catalysts causes a significant non-Faradaic increase of catalytic activity. In this work, EPOC over platinum catalyst supported on yttria stabilized zirconia (YSZ) is investigated under ambient pressure and high vacuum (HV) conditions. Under ambient pressure conditions, a Permanent-EPOC behavior is obtained upon current interruption which is related to an oxygen storage process during polarization. In addition, a custom built HV setup is used to investigate the electrochemical kinetics and EPOC over Pt/YSZ cell. During anodic polarization, three types of oxygen storage locations are identified, i.e. Pt/YSZ interface, Pt/gas interface and Pt bulk. The saturation of the Pt/YSZ interface leads to the migration of the oxygen promoter over the Pt catalyst inducing the EPOC effect. The bulk storage takes place with prolonged polarization time. Upon current interruption, the stored oxygen is released onto the Pt surface leading to Permanent-EPOC or Persistent-EPOC which is determined by the stability of surface oxygen promoter. In addition, by using an anion emission configuration, the phenomenon of 16O- emission from the Pt surface is observed indicating that the surface promoter exists in the form of 16O- originating from the YSZ lattice. The application of isotopically labeled 18O2 allows discriminating the Faradaic process (16O from the YSZ) from the non-Faradaic process (18O from the gas phase). It’s found that the EPOC effect and metal support interaction (MSI) effect are different facets of the same phenomenon, i.e. the promoting effect of oxygen species from YSZ support on the catalytic reaction taking place over the catalyst surface. By application of a novel bipolar configuration, the imposed galvanostatic step causes significant enhancement of the catalytic rate over Pt nanoparticles which opens new possibilities for the application of nano-dispersed catalysts in electrochemical promotion.
Abstract第4页
CHAPTER 1 Introduction, motivation and objectives第9-13页
CHAPTER 2 Bibliography第13-29页
    2.1 Introduction第14页
    2.2 EPOC phenomenon第14-17页
    2.3 EPOC model and experimental proofs第17-22页
    2.4 Permanent-EPOC phenomena第22-24页
    2.5 P-EPOC model and experimental proofs第24-28页
    2.6 Conclusion第28-29页
CHAPTER 3 EPOC and P-EPOC over Pt/YSZ in ambient pressure第29-46页
    3.1 Introduction第30页
    3.2 Experimental第30-32页
    3.3 Characterizations of Pt/YSZ film第32-37页
        3.3.1 Scanning electron microscopy第32页
        3.3.2 X-Ray Diffraction第32-34页
        3.3.3 Chemical titration of the Pt/YSZ catalyst第34-35页
        3.3.4 Exchange current of the Pt/YSZ catalyst第35-37页
    3.4 Results and discussion第37-45页
        3.4.1 Influence of the gas composition第37-40页
        3.4.2 Influence of polarization time on γ第40-41页
        3.4.3 Transient behavior upon linear potential sweep第41-43页
        3.4.4 Influence of cathodic polarization on P-EPOC state第43-45页
    3.5 Conclusions第45-46页
CHAPTER 4 So1id electrochemical mass spectrometry techniques under high vacuum conditions第46-64页
    4.1 Introduction第47-48页
    4.2 Experimental setup第48-54页
        4.2.1 Vacuum chamber system第49-50页
        4.2.2 Heating system第50页
        4.2.3 Mass spectrometric equipment第50-51页
        4.2.4 Electrochemical reactors第51-54页
    4.3 Preparation of the Pt/YSZ samples第54页
    4.4 System calibriations第54-58页
        4.4.1 QMS calibration第54-55页
        4.4.2 SEMS calibration第55-58页
    4.5 Results第58-61页
        4.5.1 Single chamber type SEMS第58-59页
        4.5.2 Dual chamber type SEMS第59-61页
    4.6 Discussion第61页
    4.7 Conclusion第61-64页
CHAPTER 5 Electrochemical investigation of Pt/YSZ cell under high vacuum conditions第64-80页
    5.1 Introduction第65页
    5.2 Experimental第65-67页
    5.3 Results第67-73页
        5.3.1 Cyclic voltammetry-mass spectroscopy (CV-MS) measurements第67-71页
        5.3.2 Double step chronopotentiomentry-mass spectroscopy (DSCP-MS) measurements第71-73页
    5.4 Discussion第73-79页
    5.5 Conclusion第79-80页
CHAPTER 6 Electrochemical promotion of CO combustion over Pt/YSZ under high conditions第80-91页
    6.1 Introduction第81-82页
    6.2 Experimental第82-83页
    6.3 Results第83-87页
        6.3.1 Polarization in the absent of reactive gas第83-84页
        6.3.2 Polarization in the presence of reactive gases第84-87页
    6.4 Discussion第87-89页
    6.5 Conclusion第89-91页
CHAPTER 7 Comparative investigation of metal-support interaction and electrochemical promotion over Pt nanoparticels/YSZ cell第91-110页
    7.1 Introduction第92-93页
    7.2 Experimental第93-95页
    7.3 Result and discussion第95-104页
        7.3.1 Open circuit CO combustion over Pt nanoparticles/YSZ and Pt film/YSZ cell第95-97页
        7.3.2 Polarization of Pt nanoparticles/YSZ cell第97-104页
    7.4 General discussion第104-109页
        7.4.1 Electrochemical promotion and metal-support interaction第104-105页
        7.4.2 Oxygen promoter on the metal surface第105-108页
        7.4.3 Influences of support and metal on O- emission and catalysis第108-109页
    7.5 Conclusion第109-110页
CHAPTER 8 Bipolar electrochemical promotion of CO combustion over Pt nanopartilcess/YSZ under high vacuum conditions第110-128页
    8.1 Introduction第111-112页
    8.2 Experimental第112-115页
    8.3 Results and discussion第115-125页
        8.3.1 Estimation of current bypass in planar bipolar configuration第115-118页
        8.3.2 One element bipolar cell第118-123页
        8.3.3 Multiple elements bipolar cell第123-125页
    8.4 Proposed bipolar model第125-126页
    8.5 Conclusion第126-128页
CHAPTER 9 General discussion and conclusion第128-133页
References第133-142页
Abbreviation第142-144页
Symbols第144-148页
作者简介第148-149页
Publications第149-151页
Acknowledgments第151-152页
论文购买
论文编号ABS538437,这篇论文共152页
会员购买按0.30元/页下载,共需支付45.6
不是会员,注册会员
会员更优惠充值送钱
直接购买按0.5元/页下载,共需要支付76
只需这篇论文,无需注册!
直接网上支付,方便快捷!
相关论文

点击收藏 | 在线购卡 | 站内搜索 | 网站地图
版权所有 艾博士论文 Copyright(C) All Rights Reserved
版权申明:本文摘要目录由会员***投稿,艾博士论文编辑,如作者需要删除论文目录请通过QQ告知我们,承诺24小时内删除。
联系方式: QQ:277865656