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

A Casanova,R Rincón,J Muñoz,C.O Ania,M.D Calzada

doi:10.1016/j.fuproc.2020.106630

Abstract

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.

Highlights

Since it was first discovered in 2004 [1] and owing to its outstanding mechanical, thermal, electrical and optical properties [2] graphene has been in the spotlight of scientific and technological research
We focused on evaluating the effect of the latter by thoroughly analyzing the impact of the ethanol flow introduced in the discharge in both the production rate and quality of graphene using a TIAGO torch plasma together with the formation of carbon-based gaseous by-products
Our previous work [30] demonstrated that TIAGO torch discharges open to the air can operate in a wide range of argon flows (0.15 to 5.00 L min−1) and input powers (200 to 500 W), ensuring plasma stability since the reflected power always remained below 5% of the input power

Summary

Introduction

Since it was first discovered in 2004 [1] and owing to its outstanding mechanical, thermal, electrical and optical properties [2] graphene has been in the spotlight of scientific and technological research. Being a two-dimensional layer made out of sp2-bonded carbon atoms arranged in a honeycomb structure, graphene is the quintessential building block of every other carbon materials such as fullerenes, nanotubes and graphite [3]. It is the basis for many other carbon materials obtained introducing heteroatoms in the structure of graphene [4] All these configurational and chemical modifications allow tuning graphene properties to suit particular applications that include composites [5], chemical sensors [6], energy storage [7] or the fabrication of flexible displays [8]

Methods

Results

Conclusion