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A Study in Atmosphere Dielectric Barrier Discharge Plasma Electrode A STUDY IN ATMOSPHERIC DIELECTRIC BARRIER DISCHARGE PLASMA ELECTRODE CATALYTIC EFFECT USING OXYGEN AND NITROGEN by Alex J. Gemsheim APPROVED BY SUPERVISORY COMMITTEE: Dr. Lawrence J. Overzet, Co-Chair Dr. Matthew J. Goeckner, Co-Chair Dr. Gil S. Lee Copyright 2018 Alex J. Gemsheim All Rights Reserved This thesis is dedicated to Emma. Without whom I could not have accomplished so much. A STUDY IN ATMOSPHERIC DIELECTRIC BARRIER DISCHARGE PLASMA ELECTRODE CATALYTIC EFFECT USING OXYGEN AND NITROGEN by ALEX J. GEMSHEIM, BS THESIS Presented to the Faculty of The University of Texas at Dallas in Partial Fulfillment of the Requirements for the Degree of MASTER OF SCIENCE IN ELECTRICAL ENGINEERING THE UNIVERSITY OF TEXAS AT DALLAS May 2018 ACKNOWLEDGMENTS The author thanks family and friends. Prof. Overzet, Prof. Goeckner, Prof. Lee who have guided me. I thank my lab partner Shivam Patel, who worked cooperatively with me to make this research possible. I thank Keith Hernandez and Alex Press who aided in my education. April 2018 v A STUDY IN ATMOSPHERIC DIELECTRIC BARRIER DISCHARGE PLASMA ELECTRODE CATALYTIC EFFECT USING OXYGEN AND NITROGEN Alex J. Gemsheim, MS The University of Texas at Dallas, 2018 Supervising Professors: Dr. Lawrence J. Overzet, Co-Chair Dr. Matthew J. Goeckner, Co-Chair Atmospheric dielectric barrier discharge (DBD) plasma creates a gaseous environment con- ducive to the generation of reactive species. DBD plasmas have a variety of applications in the clinical and industrial fields. During this experiment, an DBD plasma was ignited in controlled gas environments using alumina as a dielectric barrier with gold, copper, or nickel electrodes. The gas environment was formed by varying ratios of oxygen, O2, and nitrogen, N2, with trace amounts of water and carbon dioxide. The plasma transformed these diatomic molecules into reactive species, primarily ozone, O3, and nitric acid, HNO3. A higher initial percentage of oxygen will result in a higher ozone concentration. The selected electrode material also alters the concentrations of ozone and nitric acid. Additionally, the electrode material can modulate the ratio of ozone to nitric acid, providing a specific selectivity be- tween reactive species. The electrode material generating the highest ozone concentration was gold, then copper and nickel. The electrode material with the highest ratio of ozone to nitric acid was nickel at 4:1; then gold at 2:1; and copper at 1.5:1. Utilizing these parameters allows for the generation of reactive species to desired concentrations and specific selectivity. vi TABLE OF CONTENTS ACKNOWLEDGMENTS . v ABSTRACT . vi LIST OF FIGURES . ix LIST OF TABLES . xiii CHAPTER 1 INTRODUCTION . 1 CHAPTER 2 THEORY . 11 2.1 Atmospheric Dielectric Barrier Discharge Plasma . 11 2.2 Gas Chemistry . 17 2.3 Fourier Transform Infrared Spectroscopy . 20 2.4 Optical Emission Spectroscopy . 29 CHAPTER 3 HIGH RESOLUTION FTIR EXPERIMENT . 30 3.1 General Experimental Procedure . 30 3.2 High Resolution FTIR Measurements . 32 3.3 High Resolution FTIR Results . 33 3.4 Ozone FTIR Data . 33 3.5 Nitric Acid FTIR Data . 39 3.6 Carbon Dioxide FTIR Data . 48 CHAPTER 4 TIME RESOLVED FTIR EXPERIMENT . 52 4.1 Time Resolved FTIR Measurement . 52 vii 4.2 Time Resolved FTIR Results . 53 CHAPTER 5 CONCLUSION . 60 REFERENCES . 63 BIOGRAPHICAL SKETCH . 69 CURRICULUM VITAE viii LIST OF FIGURES 1.1 Siemens Experimental Setup . 1 1.2 Ellasson Experimental Setup . 2 1.3 Chen Experimental Setup . 4 1.4 Boonduang Experimental Setup . 5 1.5 Wang Experimental Setup . 6 1.6 Abdelaziz Experimental Setup . 7 1.7 Hsiao Experimental Setup . 10 2.1 Capacitively Coupled Electrodes . 12 2.2 Breakdown Regimes . 15 2.3 Electron Avalanche Effect in atmospheric DBD Plasma: Dielectric panel with two electrodes in gold, electrons in blue, neutral species in gray, positive ions in red, and the direction and relative magnitude of the electric field is shown by green arrows. 16 2.4 Vibrational and Rotational Energy Levels . 24 2.5 Michelson Interferometer . 26 2.6 Background Comparison Between Vacuum and Air . 27 2.7 Transitions of a carbon dioxide molecule, captured by a FTIR . 29 3.1 Plasma Panel Dimensions in Inches . 31 3.2 GEC Plasma Chamber and Accessories . 32 ix −1 3.3 Experimental Results: O3 from 980 to 1080 [cm ] . 34 −1 3.4 HITRAN Results: O3 from 980 to 1080 [cm ] [50] . 34 3.5 Ozone ν3 bend .................................... 35 3.6 Ozone ν1 bend .................................... 35 −1 3.7 Experimental Results: O3 from 1060 to 1220 [cm ] . 36 −1 3.8 HITRAN Results: O3 from 1060 to 1220 [cm ] [50] . 36 −1 3.9 Experimental Results: O3 from 2030 to 2140 [cm ] . 37 −1 3.10 HITRAN Results: O3 from 2030 to 2140 [cm ] [50] . 37 −1 3.11 Experimental Results: O3 from 600 to 850 [cm ] . 38 −1 3.12 HITRAN Results: O3 from 600 to 850 [cm ] [50] . 38 3.13 Ozone ν2 bend .................................... 38 3.14 Nitric Acid ν1 -OH stretching . 39 −1 3.15 Experimental Results: HNO3 from 3500-3600 [cm ] . 40 −1 3.16 Experimental Results: HNO3 from 2000-3500 [cm ] . 41 −1 3.17 Experimental Results: HNO3 from 1640-1800 [cm ] . 42 −1 3.18 HITRAN Results: HNO3 from 1640-1800 [cm ] [50] . 42 3.19 Nitric Acid ν2 NO2 asymmetric stretch . 43 3.20 Nitric Acid ν3 NO2 symmetric stretch . 43 3.21 Nitric Acid ν4 H − O − N bend . 43 x −1 3.22 Experimental Results: HNO3 from 1260-1380 [cm ] . 44 −1 3.23 HITRAN Results: HNO3 from 1260-1380 [cm ] [50] . 44 −1 3.24 Experimental Results: HNO3 from 900-1250 [cm ] . 45 −1 3.25 HITRAN Results: HNO3 from 900-1250 [cm ] [50] . 45 −1 3.26 Experimental Results: HNO3 from 700-950 [cm ] . 46 −1 3.27 HITRAN Results: HNO3 from 700-950 [cm ][50] . 46 3.28 Nitric Acid ν5 O − NO2 in-plane bend . 47 3.29 Nitric Acid ν8 NO2 out-of-plane bend . 47 −1 3.30 Experimental Results: CO2 from 2300-2400 [cm ] . 49 −1 3.31 HITRAN Results: CO2 from 2300-2400 [cm ][50] . 49 3.32 Carbon Dioxide ν3 asymmetric stretch . 49 −1 3.33 Experimental Results: CO2 from 2230-2310 [cm ] . 50 −1 3.34 HITRAN Results: CO2 from 2230-2310 [cm ][50] . 50 −1 3.35 Experimental Results: CO2 from 620-720 [cm ].................. 51 −1 3.36 HITRAN Results: CO2 from 620-720 [cm ][50] . 51 3.37 Carbon Dioxide ν2 bend . 51 4.1 Atmospheric DBD Generation, Diffusion, Decay . 53 4.2 Ozone FTIR Time Resolved Integrated Intensity Data . 56 4.3 Nitric Acid FTIR Time Resolved Integrated Intensity Data . 57 xi 4.4 Ratio O3=HNO3 FTIR Time Resolved Integrated Intensity Data . 58 4.5 Carbon Dioxide FTIR Time Resolved Integrated Intensity Data . 59 5.1 Plasma Panel Lithography Mask [cm]........................ 62 xii LIST OF TABLES 2.1 Reactions and Rate Constants. These values were compiled by [12] . 18 3.1 Nitric Acid Vibrational Modes . 39 xiii CHAPTER 1 INTRODUCTION The field of atmospheric dielectric barrier discharge (DBD) plasmas have been widely studied because of their potential applications[1][2]. The DBD plasma creates an environment of reactive species, which was used in the first ozone generator[3]. The reactive gas chemistry can also be employed for equipment and wound sterilization[4][5][6][7][8][9][10][11]. If a DBD were placed in contact with, or submerged in water, the resulting reactions form an acidic solution[12]. This process can be used in water treatment facilities. NASA has proven DBD plasmas can be utilized on an airfoil to reduce turbulence [13]. Plasma forces the surrounding air in a particular direction, acting as an actuator to create laminar flow around the airfoil. Siemens first studied the gas chemistry of DBD plasmas in 1857, for the production of ozone [3]. In his experiment, he used concentric glass tubes to allow the flow of oxygen between the tubes, as seen in Figure 1.1. Glass is a solid dielectric. Here it formed a barrier between the electrodes, and corresponds to the dielectric barrier of a DBD. Tin electrodes Figure 1.1. Siemens Experimental Setup covered the outside of the outer tube and the inside of the inner tube. When the electrodes were connected to a spark generator the oxygen broke down forming a DBD plasma. This was a new plasma discharge structure, and it ignited decades of research to discover the nature of the DBD plasma and the resulting reactive gas chemistry. The first detailed study of the structure of DBD plasma was by Buss in 1932[14]. With the use of Lichtenberg figures, he described the filamentary nature of the micro-discharge. 1 The discharge was not uniform in space, but consisted of a large number of microscopic dis- charges forming and terminating rapidly. From this, a series of models, Homogeneous[15][16], Avalanche[5], and Numerical[17][18] were developed to attempt to capture one or multiple attributes of the discharge. These attributes include energy distribution[19], particle motion, discharge structure, plasma formation and termination, and chemical species reactions. How- ever, models considering only ground state atoms and molecules failed to properly predict all of the reactive oxygen species observed in DBD plasmas. In 1986, Ellasson, Hirth, and Kogelschatz expanded upon the knowledge of both plasma structure and gas chemistry, which propelled previous DBD models to near current stan- dards. They implemented a cylindrical micro-discharge structure and excited atomic and molecular states, which greatly altered the model of generated species [20]. The experimen- tal configuration confined the discharge between two concentric tubes, shown in Figure 1.2. To achieve this, the interior of a 1.8 [mm] thick Pyrex tube was coated with aluminum to Figure 1.2.
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