Preparation and synthesis of carbon nanomaterials from 1-hexanol by solution plasma process with Ar/O₂ gas bubbles

This study presents the simple and catalyst-free methods for synthesizing carbon nanomaterials from 1-hexanol alcohol by using stable solution plasma process by varying the argon (Ar), oxygen (O₂), and Ar and O₂ mixtures plasma working gas bubble. The structural characteristics of carbon nanomaterials are measured by transmission electron microscopy, Raman spectroscopy, and X-ray diffraction. The discharge characteristics are examined based on the discharge voltage, current, and optical emission spectrometer (OES) techniques. By using the external Ar gas bubble discharge during solution plasma process, the size of carbon nanoparticle and discharge voltage are decreased compared to the no gas case and the discharge current is increased, which would be due to the increase of plasma energy and enhancement of the square of plasma-liquid contact to plasma volume. By using the external O₂ gas bubble discharge during solution plasma process, whereas, the size of carbon nanoparticle is increased compared to the no gas case and the discharge voltage and current are decreased, which would be due to the production of relatively high amounts of oxygen radicals, resulting in the flame synthesis. Raman spectra results show that the degree of graphitization of the carbon nanomaterials synthesized with external Ar 150 and O₂ 50 standard cubic centimeter per minutes (sccm) mixtures gas bubble during solution plasma process is observed to be greater than that of the carbon nanomaterials synthesized with the only Ar or O₂ gas bubble. This solution plasma process by varying the plasma working gas mixtures can potentially be used for the precise nanomaterial synthesis.