Introduction to Pulsed Voltammetric Techniques: DPV, NPV and SWV I
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07 Chapter2.Pdf
22 METHODOLOGY 2.1 INTRODUCTION TO ELECTROCHEMICAL TECHNIQUES Electrochemical techniques of analysis involve the measurement of voltage or current. Such methods are concerned with the interplay between solution/electrode interfaces. The methods involve the changes of current, potential and charge as a function of chemical reactions. One or more of the four parameters i.e. potential, current, charge and time can be measured in these techniques and by plotting the graphs of these different parameters in various ways, one can get the desired information. Sensitivity, short analysis time, wide range of temperature, simplicity, use of many solvents are some of the advantages of these methods over the others which makes them useful in kinetic and thermodynamic studies1-3. In general, three electrodes viz., working electrode, the reference electrode, and the counter or auxiliary electrode are used for the measurement in electrochemical techniques. Depending on the combinations of parameters and types of electrodes there are various electrochemical techniques. These include potentiometry, polarography, voltammetry, cyclic voltammetry, chronopotentiometry, linear sweep techniques, amperometry, pulsed techniques etc. These techniques are mainly classified into static and dynamic methods. Static methods are those in which no current passes through the electrode-solution interface and the concentration of analyte species remains constant as in potentiometry. In dynamic methods, a current flows across the electrode-solution interface and the concentration of species changes such as in voltammetry and coulometry4. 2.2 VOLTAMMETRY The field of voltammetry was developed from polarography, which was invented by the Czechoslovakian Chemist Jaroslav Heyrovsky in the early 1920s5. Voltammetry is an electrochemical technique of analysis which includes the measurement of current as a function of applied potential under the conditions that promote polarization of working electrode6. -
An Exploration of Basic Processes for Aqueous Electrochemical Production of Hydrogen from Biomass Derived Molecules
University of Tennessee, Knoxville TRACE: Tennessee Research and Creative Exchange Doctoral Dissertations Graduate School 12-2017 An Exploration of Basic Processes for Aqueous Electrochemical Production of Hydrogen from Biomass Derived Molecules Brian Fane University of Tennessee, Knoxville, [email protected] Follow this and additional works at: https://trace.tennessee.edu/utk_graddiss Part of the Catalysis and Reaction Engineering Commons, Inorganic Chemistry Commons, and the Other Chemical Engineering Commons Recommended Citation Fane, Brian, "An Exploration of Basic Processes for Aqueous Electrochemical Production of Hydrogen from Biomass Derived Molecules. " PhD diss., University of Tennessee, 2017. https://trace.tennessee.edu/utk_graddiss/4742 This Dissertation is brought to you for free and open access by the Graduate School at TRACE: Tennessee Research and Creative Exchange. It has been accepted for inclusion in Doctoral Dissertations by an authorized administrator of TRACE: Tennessee Research and Creative Exchange. For more information, please contact [email protected]. To the Graduate Council: I am submitting herewith a dissertation written by Brian Fane entitled "An Exploration of Basic Processes for Aqueous Electrochemical Production of Hydrogen from Biomass Derived Molecules." I have examined the final electronic copy of this dissertation for form and content and recommend that it be accepted in partial fulfillment of the equirr ements for the degree of Doctor of Philosophy, with a major in Chemical Engineering. Thomas Zawodzinski, -
Hydrodynamic Electrodes and Microelectrodes
CHEM465/865, 2004-3, Lecture 20, 27 th Sep., 2004 Hydrodynamic Electrodes and Microelectrodes So far we have been considering processes at planar electrodes. We have focused on the interplay of diffusion and kinetics (i.e. charge transfer as described for instance by the different formulations of the Butler-Volmer equation). In most cases, diffusion is the most significant transport limitation. Diffusion limitations arise inevitably, since any reaction consumes reactant molecules. This consumption depletes reactant (the so-called electroactive species) in the vicinity of the electrode, which leads to a non-uniform distribution (see the previous notes). ______________________________________________________________________ Note: In principle, we would have to consider the accumulation of product species in the vicinity of the electrode as well. This would not change the basic phenomenology, i.e. the interplay between kinetics and transport would remain the same. But it would make the mathematical formalism considerably more complicated. In order to simplify things, we, thus, focus entirely on the reactant distribution, as the species being consumed. ______________________________________________________________________ In this part, we are considering a semiinfinite system: The planar electrode is assumed to have a huge surface area and the solution is considered to be an infinite reservoir of reactant. This simple system has only one characteristic length scale: the thickness of the diffusion layer (or mean free path) δδδ. Sometimes the diffusion layer is referred to as the “Nernst layer” . Now: let’s consider again the interplay of kinetics and diffusion limitations. Kinetic limitations are represented by the rate constant k 0 (or equivalently by the 0=== 0bα b 1 −−− α exchange current density j nFkcred c ox ). -
Μstat 4000P Multi Potentiostat
µStat 4000P Multi Potentiostat 01 Ref. STAT4000P Following the format of our multipotentiostats with a size of only 22x20x7 cm, includes 4 channels that can act at the same time as 4 independent potentiostats; it also includes one multichannel that can act as a poten- tiostat where up to 4 working electrodes share an auxiliary and a reference electrode. With µStat 4000P users can perform up to 4 different electrochemical techniques at the same time; or carry out the study of one technique’s parameter in just one step by applying the same electrochemical technique in several channels but selecting different values for the parameter under study. These are just exam- ples of the enormous capabilities that our new instrument offers. µStat 4000P can be applied for Voltammetric or Amperometric measurements, including 12 electroanalytical techniques. In addition, µStat 4000P owners can later upgrade their instrument to a µStat 4000P by just purchasing an extension. This self-upgrade does not require any hardware modification, but it is implemented by means of a Galvanostat software update kit. This Multi Potentiostat is Li-ion Battery powered (DC charger adaptor also compatible), and can be easily connected to a PC via USB or through Wireless connection. µStat 4000P is controlled by the powerful software “DropView 8400” which is included and that allows plotting of the measurements and performing the analysis of results. DropView software provides powerful functions such as experimental control, graphs or file handling, among others. Available -
Basics and Applications of a Quartz Crystal Microbalance Monitoring Surface Interactions Via Small-Scale Mass Changes
Basics and Applications of a Quartz Crystal Microbalance CORROSION BATTERY TESTING Monitoring Surface Interactions via Small-scale Mass Changes COATINGS PHOTOVOLTAICS gamry.com Contents Basics of QCM ........................................................................................................................3 Calibration of a QCM ................................................................................................... 13 Investigation of a Thin Polymer Film ..........................................................................21 The eQCM 10M System ..................................................................................................... 26 The QCM-I System .............................................................................................................. 27 References .......................................................................................................................29 Additional Resources .................................................................................................... 30 2 gamry.com Basics of a Quartz Crystal Microbalance This section provides an introduction to the quartz crystal microbalance (QCM) which is an instrument that allows a user to monitor small mass changes on an electrode. The reader is directed to the numerous reviews 1 and book chapters1 & 2 for a more in-depth description concerning the theory and application of the QCM. A basic understanding of electrical components and concepts is assumed. The two major points of this section are: -
A Practical Organic-Mediated Hybrid Electrolyser That Decouples
Electronic Supplementary Material (ESI) for Chemical Science. This journal is © The Royal Society of Chemistry 2018 Supplementary Information for: A Practical Organic-Mediated Hybrid Electrolyser that Decouples Hydrogen Production at High Current Densities Niall Kirkaldy,a Greig Chisholm,a Jia-Jia Chena and Leroy Cronin*a a WestCHEM, School of Chemistry, University of Glasgow, University Avenue, Glasgow, G12 8QQ, UK * Corresponding author, [email protected] 1 Contents SI-1. General Experimental Remarks .................................................................................................. 3 SI-2. Electrochemical Characterisation ............................................................................................... 4 SI-3. Gas Headspace Measurements................................................................................................... 6 SI-4. Hybrid PEME Construction and Operation ................................................................................. 7 SI-5. PEME Characterisation Methods ................................................................................................ 8 SI-6. PEME Efficiency Calculations .................................................................................................... 10 SI-7. Cost Calculations ....................................................................................................................... 11 2 SI-1. General Experimental Remarks 9,10-anthraquinone-2,7-disulfonic acid disodium salt was purchased from Santa Cruz Biotechnology -
Pulse Voltammetry Software Brochure
Data Analysis density. This feature is particularly useful for comparing data from electrodes of different areas. The analysis of the software data is performed in the Echem Analyst. Specific analysis routines have been created to Baseline Add: Baselines can be added to the data graph by either drawing a Freehand Line or by extrapolating a handle this software data files. The general features of the Echem Analyst are described in a separate brochure entitled part of the baseline with the Linear Fit feature. Redefining Electrochemical Measurement “Overview of Gamry Software.” Integrate: Integration of the current in Differential Pulse These specific routines include: Voltammetry and Square Wave Voltammetry is possible by defining a baseline and then selecting the portion of the Pulse Voltammetry Software Peak Find: Use the Region Selector button to select a curve you want to integrate. Then select Integrate from the portion of the curve that includes the region where the drop-down menu and the result is reported on the curve The Pulse Voltammetry Software adds Differential Pulse peak is located. Click on the Peak Find button to find the and also on a new tab. This software incorporates the following pulse techniques: peak position and the peak height. A perpendicular line is Voltammetry, Square Wave Voltammetry, and other drawn on the chart from the peak to the baseline. Background Subtract: A background file can be recognized pulse voltammetry techniques to the Gamry ● Square Wave subtracted from the current active data file by selecting software product family. For qualitative and mechanistic ● Square Wave Stripping Subtract from the menu and choosing the file. -
Supporting Information Redox-Active and Semi-Conducting Donor
Electronic Supplementary Material (ESI) for Journal of Materials Chemistry A. This journal is © The Royal Society of Chemistry 2018 Supporting Information Redox-active and Semi-conducting Donor-Acceptor Conjugated Microporous Polymers as Metal-free ORR Catalysts Syamantak Roy,a Arkamita Bandyopadhyay,b Mrinmay Das,c Partha Pratim Ray,c Swapan K. Patib and Tapas Kumar Maji*a a Molecular Materials Laboratory, Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore-560064, India b New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore- 560064 c Department of Physics, Jadavpur University, Kolkata -700032 Table of Contents Physical Measurements ..................................................................................................................2 Computational Details ....................................................................................................................3 Electrochemical Measurements ......................................................................................................3 Experimental Section......................................................................................................................5 IR Spectra .......................................................................................................................................7 PXRD .............................................................................................................................................7 -
Emstat-Go-Description.Pdf
z Rev. 1-2019 EmStat Go potentiostat ...............................................................................................................2 Sensor Extension module .........................................................................................................2 Sleeves in any color .................................................................................................................3 Modular design ........................................................................................................................3 Optional battery for connecting via Bluetooth ...........................................................................3 Reduce your time-to-market ....................................................................................................4 Supported techniques ..............................................................................................................4 Voltammetric techniques ......................................................................................................4 Techniques as a function of time ..........................................................................................4 Custom software options .............................................................................................................5 Specifications of general parameters ...........................................................................................6 General pretreatment............................................................................................................6 -
Development and Evaluation of a Calibration Free Exhaustive Coulometric Detection System for Remote Sensing
University of Louisville ThinkIR: The University of Louisville's Institutional Repository Electronic Theses and Dissertations 5-2014 Development and evaluation of a calibration free exhaustive coulometric detection system for remote sensing. Thomas James Roussel University of Louisville Follow this and additional works at: https://ir.library.louisville.edu/etd Part of the Mechanical Engineering Commons Recommended Citation Roussel, Thomas James, "Development and evaluation of a calibration free exhaustive coulometric detection system for remote sensing." (2014). Electronic Theses and Dissertations. Paper 1238. https://doi.org/10.18297/etd/1238 This Doctoral Dissertation is brought to you for free and open access by ThinkIR: The University of Louisville's Institutional Repository. It has been accepted for inclusion in Electronic Theses and Dissertations by an authorized administrator of ThinkIR: The University of Louisville's Institutional Repository. This title appears here courtesy of the author, who has retained all other copyrights. For more information, please contact [email protected]. DEVELOPMENT AND EVALUATION OF A CALIBRATION FREE EXHAUSTIVE COULOMETRIC DETECTION SYSTEM FOR REMOTE SENSING by Thomas James Roussel, Jr. B.A., University of New Orleans, 1993 B.S., Louisiana Tech University, 1997 M.S., Louisiana Tech University, 2001 A Dissertation Submitted to the Faculty of the J. B. Speed School of Engineering of the University of Louisville in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy Department of Mechanical Engineering University of Louisville Louisville, Kentucky May 2014 Copyright 2014 by Thomas James Roussel, Jr. All rights reserved DEVELOPMENT AND EVALUATION OF A CALIBRATION FREE EXHAUSTIVE COULOMETRIC DETECTION SYSTEM FOR REMOTE SENSING By Thomas James Roussel, Jr. -
High Speed Controlled Potential Coulometry
c1CYCLIC CHELONO, DIFPU- c2SOLVE GENERATED EQUA- 903 FORMAT (5HRR =, F10.5, SION CONTROLL, PLANE TION BEGIN AT 96 READ 8HFRACT =, F10.5) ELECTRODE, READ IN K IN NOSIG FOR ACCURACY GO TO 920 NOSIG RR FRACT, TWO 96 IF(M- 1)300,100,102 300 PRINT905 SOLUBLE ElPECIES 100 Z=Y 905 FORRSAT (2X,5HEItROR) READ 900,K,NOSlG, RR, M=M+l 920 STOP FRACT 102 IF (Z) 98,200,99 EXD DIMENSION X (100),T (1 00) , 98 IF (Y) 71,200,73 END R(100) 99 IF (Y) 73,200,71 C GENERATION OF EQUA- 71 T(N) = T(N) + 10.0 **(-LA) LITERATURE CITED TIONS GO TO 10 (1) Alden, J. R., Chambers, J. Q., Adams, DO200N = 1,K 73 T(N) = T(K) - 10.0 **(-LA) R. N., J. Electroanal. Chem. 5, 152 T(N) = 0.0 LA=LA+I (1963). M=l 199 IF (NOSIG - LA) 300,200,71 (2) Bard, A. J., ANAL. CHEM. 33, 11 (1961). LA = 0 200 CONTIXUE (3) Churchill, R. V., “Operational Mathe- 10 DO 80 I = 1,N c3EQUATION SOLVED PRINT matics,” p. 39, McGraw-Hill, New York, SUM = 0.0 ANSWER 1958. DO 60 J = I,N DO201 J = 1,K,2 (4) Galus, Z., Lee, H. Y., Adams, R. N., = 201 R(J) = T(J)/T(J 1) J. Electroanal. Chem. 5, 17 (1963). 60 SUM SUM -- T(J) + (5) Murra,y, R. W., Reilley, C. N., Ibid., X(1) = SQRTF(SUM) PRINT 903, RR, FRACT 3, 182 (1962). 80 CONTIXUE PRINT 901 (6) Piette, L. -
Walljet Electrochemistry: Quantifying Molecular Transport Through Metallopolymeric and Zirconium Phosphonate Assembled Porphyrin Square Thin Films
4422 Langmuir 2004, 20, 4422-4429 Walljet Electrochemistry: Quantifying Molecular Transport through Metallopolymeric and Zirconium Phosphonate Assembled Porphyrin Square Thin Films Aaron M. Massari, Richard W. Gurney, Craig P. Schwartz, SonBinh T. Nguyen, and Joseph T. Hupp* Department of Chemistry and the Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113 Received January 12, 2004. In Final Form: March 7, 2004 By employing redox-active probes, condensed-phase molecular transport through nanoporous thin films can often be measured electrochemically. Certain kinds of electrode materials (e.g. conductive glass) are difficult to fabricate as rotatable disks or as ultramicroelectrodessthe configurations most often used for electrochemical permeation measurements. These limitations point to the need for a more materials- general measurement method. Herein, we report the application of walljet electrochemistry to the study of molecular transport through model metallopolymeric films on indium tin oxide electrodes. A quantitative expression is presented that describes the transport-limited current at the walljet electrode in terms of mass transport through solution and permeation through the film phase. A comparison of the film permeabilities for a series of redox probes measured using the walljet electrode and a rotating disk electrode establishes the accuracy of the walljet method, while also demonstrating similar precision for the two methods. We apply this technique to a system consisting of zirconium phosphonate assembled films of a porphyrinic molecular square. Transport through films comprising three or more layers is free from significant contributions from pinhole defects. Surprisingly, transport through films of this kind is 2-3 orders of magnitude slower than through films constructed via interfacial polymerization of nearly identical supramolecular square building blocks (Keefe; et al.