Advancements in Free-Standing Graphene Synthesis Using Electrodeless Microwave Plasma

For the past decade, despite the intrinsic properties of graphene, practical industrial application remains unfeasible, as traditional top-down and bottom-up methods struggle to attain the intricate balance necessary for quality, scalability, and cost-effective graphene production. Thus, there is an urgent need to seek advancement in technology beyond traditional methods with plasma-assisted graphene production. This review specifically focuses on the exploration of electrodeless microwave plasma (EMP), highlighting its key attributes such as high energy efficiency, substrate-free/electrodeless configurations, and tunable parameters. Though well-established technology, the underlying working mechanisms, optimizing intricate interplay of key parameters, and addressing unclear plasma setup have urged the need for deeper investigation. Furthermore, the scarcity of extensive reviews on EMP, combined with previous works that typically cover a broader range of microwave plasma technologies, has created an opportunity for this review to stand out. This review uniquely positions itself to address the knowledge gap, providing the specific types of microwave plasma systems and insights into the influence of each parameter on graphene formation, supported by relevant characterizations. Additionally, the review discusses future prospects for achieving scalable, efficient, and sustainable production with the incorporation of computational modeling and technologies to optimize parameters and develop an eco-efficient design.