Report

Teaser, summary, work performed and final results

Periodic Reporting for period 1 - PEGASUS (Plasma Enabled and Graphene Allowed Synthesis of Unique nano Structures)

Teaser

PEGASUS ambitious goal is to translate the unique properties of plasmas into extraordinary material characteristics and create novel forms of matter via plasma-driven controllable self-organization of hybrid atomic-thick planes and their 3D architectures. The key ambition is...

Summary

PEGASUS ambitious goal is to translate the unique properties of plasmas into extraordinary material characteristics and create novel forms of matter via plasma-driven controllable self-organization of hybrid atomic-thick planes and their 3D architectures. The key ambition is to develop a rapid, single-step, highly cost-efficient, environmentally friendly and versatile method, based on plasma processes, for selective large-scale synthesis of tailored free-standing N-graphene (nitrogen-doped graphene) sheets and N-graphene based free standing hybrid materials as well as unique vertical N-graphene arrays grown on metal substrates via breakthrough research on plasma-enabled singular assembly pathways. The hybrid materials addressed are: N-graphene/polymer, N-graphene/metal oxides and N-graphene/metal oxides/polymer nanocomposites. The targeted electrochemical performance of the nano-architectures considered will allow their assessment as electrode constituents in a scheduled proof-of-concept supercapacitor device. The strategic purpose is to design and manufacture of a proof-of-concept machine for large-scale N-graphene production. The synergy between plasma physics and mechanical, electrochemical and hi-tech engineering expertise is the driving force boosting the innovative approach pursued by this project, spanning from fundamental knowledge to appliance prospects.
The exclusive mechanisms to control the energy and matter transfer process at nanoscales make plasmas a Key Enabling Technology for controllable, catalyst/hazardous-free synthesis of complex nano-architectures, in tune with the pursue of environmental sustainability. Thus, the project fosters breakthrough research enabling a new industrial platform for complex hybrid 2D carbon-based materials manufacturing, and the creation of new tailored N-graphene synthesis routes that will provide a unique and reliable source of graphene-based materials of high purity, maximum conductivity and proper morphology, avoiding the use of harsh chemicals and lengthy batch processes. The successful accomplishment of the project will pave the way to implement new local manufacturing capabilities in the participating countries. The R&D programme with its rich training value will lead to greater European competitiveness. This project fosters knowledge, creativity and collaboration, the key building blocks for innovation. Moreover, PEGASUS contribution aims to go beyond the scientific scope, helping to bridge economical/social gaps in tune with the EU ambitions.

Work performed

Main scientific and technological achievements during the first year:
• Microwave-driven plasmas were, for the first time, successfully applied to the controllable and direct synthesis of high-quality free-standing N-graphene sheets, via a single-step process at atmospheric pressure and at high yield. The selective synthesis of free-standing N-graphene sheets was achieved via synergistic tailoring of the plasma environment and the “cold” outlet gas flow. To this end, reproducible results regarding N-doping level, oxygen functionalities and sp2 carbons have been obtained. Theoretical modelling has enlightened the main mechanisms of N-graphene formation and the role of different nitrogen containing radicals in the process.
• The first results obtained provide substantial evidence that microwave plasma technologies can be used as a competitive and disruptive alternative to chemical methods in the controlable, cost-effective manufacturing of high-quality free-standing N-graphene sheets.
• Successful development of large-scale plasma reactor design concept.
• Successful demonstration of the applicability of the N-graphene sheets produced for several new applications.
• Assessement of the electrochemical performance of the as-synthesized N-graphene sheets, demonstrating its high conductivity and its potentential as a highly-conductive matrix in N-graphene/metal oxide composites.
• Successful demonstration of microwave/RF plasma-assisted fabrication of vertical graphene sheets on different substrates, including metallic ones, applying a top-down synthesis approach as the first step towards vertical N-graphene fabrication.
• Successful exploration of a bottom-up approach for the large-scale synthesis of graphene/N-graphene from polymer gels.
• Successful demonstration of RF capacitively coupled plasma-assisted fabrication of graphene/N-graphene based polymer composites. Successful rinting of N-graphene structures on polyaniline films.
Strategic achievements:
• Formation of an ever-growing user community of scientists to explore the new physics and application opportunities related with free-standing N-graphene sheets and N-graphene/polymer composites.

Final results

A rapid, single-step, cost-efficient, high-yield and environmentally friendly method for the selective synthesis of tailored graphene/N-graphene free-standing sheets at atmospheric pressure is being further improved. It relies on a plasma process that does not employ heavy vacuum systems, metal catalysts or substrates, and that allows the use of carbon/nitrogen precursors in liquid or gas states. The main advantage of this approach is the achievement of a very-high energy-density in the plasma reactor in a controlled way, which allows effective control over the energy and the material fluxes towards growing nanostructures at the atomic scale level. This is achieved via proper reactor design and tailoring of the plasma environment in a synergistic way. The key advantages of the novel process include the manufacturing of N-graphene sheets at atmospheric ambiance via a single step, the control of the nitrogen doping content and distribution.
Furthermore, the first step for a fast and controllable (~8 min) microwave/RF plasma-assisted synthesis of vertically aligned carbon nanowalls (multilayer graphenes) on different substrates was performed, applying various approaches at low-pressure condition. The height of the manufactured walls is about 2 micrometers. In addition, controllable RF plasma manufacturing of vertically aligned multilayer graphenes on metal substrates at variable temperatures was also performed. The manufactured carbon nanowalls were confirmed to be indeed 2D graphene nanowalls, by synchrotron radiation-based X-ray spectroscopies and Raman spectroscopy analysis. Moreover, microwave plasma-assisted growth of 3D graphene structures on metal substrates has been achieved at atmospheric pressure conditions.
PEGASUS project opens a new way to offer tailor-made 2D carbon materials and their 3D architectures, via a cheaper and environmentally friendly route. The impact is definitely a breakthrough as it combines Europe’s most ambitious goals in nanomaterials as Key Enabling Technologies: disruptive properties via a cheap “green” route that allow the replacement of existing materials with new cost-effective, higher performance ones, with the resulting processes embodying apparent economic impact. Given the uniqueness of 2D structures it is likely that these materials will reveal new and untapped extraordinary properties, providing several innovative opportunities. The developments in this plasma technology field will certainly have high potential impact for application such as energy storage and conversion devices, conductive inks, membranes, sensors, metamaterials, carbon materials with low secondary yield, biosensors and polymer injection systems.

Website & more info

More info: https://www.ipfn.tecnico.ulisboa.pt/PEGASUS/.