Plasmachemical Synthesis of Carbon Suboxide

Abstract

A nonthermal carbon monoxide plasma is known to produce a solid deposition which is thought to be a polymer of carbon suboxide (C3O2); however there are very few investigations of this deposition in the literature. This thesis contains an analysis of the theoretical thermodynamics and kinetics of carbon suboxide formation as well as experimental results. The theoretical analysis suggests that carbon suboxide may be an equilibrium product even at ambient conditions but favors lower temperatures; furthermore if solid carbon is considered to be kinetically limited, and therefore not a product, then carbon suboxide is more likely to be a product under these pseudo-equilibrium conditions. Experimentally, solid films were produced in a dielectric barrier discharge (DBD) containing pure carbon monoxide. Optical emission spectroscopy was used to analyze the plasma and models of the emission spectra were created to determine the plasma temperatures. Deposition rates were determined to be on the order of 0.2 mg/min at a power of about 10W; it is expected however that these conditions are not optimized. The overall kinetics of carbon suboxide was analyzed and optimal conditions for operation can be estimated. Characterization of the solid depositions were carried out using Solid State Nuclear Magnetic Resonance (NMR), Fourier Transform Infrared Spectroscopy (FTIR), Electrospray Ionization Mass Spectroscopy (ESI-MS), and Matrix-assisted Laser Desorption Ionization Mass Spectroscopy (MALDI-MS). The characteristics of the film are very comparable to hydrolyzed carbon suboxide polymer suggesting that carbon suboxide polymer were in fact created in the carbon monoxide plasma at atmospheric conditions.