Characterization of Ethanol Plasma Glow Discharge, Decomposition in Several Species and Solid Film Formation

Abstract

Ethanol plasma produced in low pressure with constant flux has been characterized in situ by optical emission spectroscopy (OES) and a Langmuir probe. From these methods, hydrogen and carbon monoxide are the main products from the ethanol decomposition in the plasma. In addition, C 2 , OH, CH, O + 2 , and H α species were identified. The values obtained for electron density and temperatures were 1.26 × 10 18 m -3 and 1.16 eV, respectively. The mass deposited (MD) on the electrode was analyzed by scanning electron microscopy and Fourier transform infrared spectroscopy (FT-IR) techniques. The morphology of the MD changes as a function of the discharge time from thin film to a cluster formation. The FT-IR results show that the main absorbance corresponds with C-H bonds, indicating that the mass deposit is formed mainly by this molecular fraction, which agrees with the CH species identified as the less abundant molecule in the plasma by OES. In addition, C≡C, O-H, C-H, C=C, and C-O bonds were identified.