Optimizing high-quality graphene nanoflakes production through organic (bio)-precursor plasma decomposition

Atmospheric pressure plasma-based technique for the decomposition of biofuels allows obtaining high-quality graphene powder in one step, without the use of neither metal catalysts nor specific substrates. Despite the numerous advantages of this technology as compared to others, it is necessary to optimize the process to produce high-quality graphene at industrial scale. In this research, the influence of the ethanol flows in the 2.00 to 4.00 g h−1 range on the production rate and the quality of graphene has been thoroughly assessed, through a deep characterization of the synthetized material by various techniques. The graphene production rate steadily increased for ethanol flows increasing from 2.00 to 3.40 g h−1, presenting a maximum rate of 1.45 and 1.55 mg min−1 for 2.90 and 3.40 g h−1, respectively. Higher ethanol flows lead to a decrease in the production rate, favouring the formation of other carbon-based by-products such as methane and ethylene. High-quality graphene is formed in all plasma conditions, with the lowest number of defects being obtained for an ethanol flow of 2.90 g h−1 together with hydrogen and carbon monoxide as main gaseous by-products. [Display omitted] •Production of Graphene by ethanol decomposition by microwave plasma•Optimization of plasma experimental conditions for high-quality graphene production•Acting on the ethanol flow, a max. 1.55 mg min−1 graphene production rate is obtained.•Raman spectroscopy, HRTEM image, XRD and XPS analysis confirm high-quality graphene.