Investigation of Deposits in a Carbon Monoxide DBD Robert Geiger Advisor: Dr. David Staack Texas A&M Mechanical Engineering Plasma Engineering & Diagnostics Laboratory (PEDL)

Outline Introduction Experimental Setup Results Future Work Conclusion

Introduction

Hydrocarbon Utilization CH4 (CxHy) CO2 H2O CO H2 Combustion Fischer Troscph Ethanol Hydrogen CO Polymer ? H=393.5 kJ/mol CO2 H=241 kJ/mol H2O H=110 kJ/mol CO2

Molecular Forms of C and O CO CO 2 C 3 O 2 Carbon Suboxide ? (Matthias Ballauff, et. al Angew. Chem. Int. Ed. 2004, 43)

Carbon Monoxide at Really High Pressures Lipp M J et al 2005 Nat. Mater V V Brazhkin 2006 J. Phys.: Condens. Matter

EXPERIMENTAL SECTION

Experimental Setup Power Supply: V max ~ 10 kV I max ~ 40 mA Freq ~ 25 – 30 kHz P ~ 40W-150W

DBD Reactor Color Variations

Deposition Rate

Increasing Flow 180 ccm 870 ccm1700 ccm ~ 30W~50W~100W Increasing Power Also, gas temperature and surface temperature do not cause the different film colors.

FTIR – Comparison with High Pressure Film (High Pressure Film FTIR data taken from: Lipp M J et al 2005 Nat. Mater )

Film Properties C:O ~ (XPS) Solubility Water (Hydrates) Insoluble Acetone Ethanol Solubility allows for spin coating and layer by layer film growth Before After Hydration C:O ~

Kinetics Proposed mechanism from several sources McTaggart FK PIasma Chemistry in Electrical Discharges (1967)

Kinetic Model in Development Still need to add CO* reactions C(s) reactions Surface reactions

Kinetic Model in Development

CO CO2 C3O2 C3O2(p) Const T Te = 1 eV ne = cm -3 ne = const

Emission Spectroscopy Angstrom CO Bands (B 1 Σ + – A 1 π) C2 Swan Bands (d 3 π– a 3 π) Herzberg CO Bands (C 1 Σ + – A 1 π)

Emission Spectroscopy - Temperature

Future Work Determine the polymer structures (NMR) and chain length Characterize polymers and determine their properties Complete the kinetic model and compare with experimental Determine optimum production parameters

Conclusion Interesting films can be formed as fast as 1 mg/min at 50W with solely carbon and oxygen atoms These films appear similar in structure to high pressure CO polymers Increased power darkens the film and increases deposition rate Color changes do not alter the FTIR A kinetic model in under development The C2 swan, CO angstrom and CO Herzberg bands enables temperature measurements in the visible range

References Lipp M J et al 2005 Nat. Mater V V Brazhkin 2006 J. Phys.: Condens. Matter McTaggart FK PIasma Chemistry in Electrical Discharges (1967) P.C.Cosby, J. Chem. Phys. 98,9560(1993). K.M.D’Amico,and A.L.S.Smith, J.Phys.D: Appl. Phys. 10,261 (1977) Questions?

Solubility and Hydration BeforeAfter

CO  CO 2 + C (gr) Metastability of CO

FTIR – Comparison with High Pressure Film (High Pressure Film FTIR data taken from: Lipp M J et al 2005 Nat. Mater )

C/O ratios ranging from XPS Ref: INSERT REF

Low Power Setting (~60W) Color Changes with Time and Power 30 min60 min 120min180min Hi Power Setting (~130W, 180 min) Low Power Setting (~60W, 180 min)