N-Graphene-Metal-Oxide(Sulfide) hybrid Nanostructures: Single-step plasma-enabled approach for energy storage applications

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 430; p. 133153
• Main Authors: Dias, A., Bundaleska, N., Felizardo, E., Tsyganov, D., Almeida, A., Ferraria, A.M., Botelho do Rego, A.M., Abrashev, M., Strunskus, Th, Santhosh, N.M., Cvelbar, U., Zavašnik, J., Montemor, M.F., Almeida, M.M., Carvalho, Patrícia A., Kissovski, J., Alves, L.L., Tatarova, E.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15-02-2022
• Subjects: Hybrid nanostructures; Microwave plasmas; N-graphene; Plasma-based synthesis; Microwave plasmas; Hybrid nanostructures; Plasma-based synthesis; N-graphene
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2021.133153

•Novel plasma-based approach to design hybrid N-Graphene-metal-based nanostructures is created.•The synthesis method is controllable, single-step and at atmospheric conditions.•Metal oxide/sulfide anchored N-graphene at large scale (~19 mg/min) are produced.•Electrode for supercapacitor with metal oxide/sulfide-N-graphene was developed.•The electrode demonstrated promising specific capacitances ∼ 273 F.g−1 at 0.5 A.g−1.
Hybrid graphene-based nanostructures are considered promising materials for energy storage applications. However, the synthesis of high-quality hybrid graphene nanostructures at high yields is challenging. In the present work we propose a novel, single-step microwave plasma-enabled approach to synthetize customizable hybrid graphene-based nanostructures at high-yield while preserving their quality. Hybrid N-graphene (nitrogen-doped graphene) metal-based nanostructures, for instance, can be produced at a rate of ∼ 19 mg/min. The high energy density region of a microwave plasma provides sufficient energy and “building particles” fluxes towards the low-energy density plasma afterglow for the processes of assembly and growth of N-graphene sheets. Simultaneously, a controlled jet of metal-oxide(-sulfide) microparticles is sprayed into the plasma afterglow region where they bind to N-graphene sheets. Methane/methylamine are used as carbon and nitrogen precursors, combined with micron-sized MnO2 and oxy-MnS particles to synthesize the hybrid structures. As a result, nano-sized (∼10–30 nm) MnOx particles decorated N-graphene (4.6 at. N%) and oxidized metal sulfide anchored N-graphene sheets (3.1 at. N%) are produced at atmospheric conditions. High structural quality and distribution of metal-based nanostructures on N-graphene sheets are revealed using transmission and scanning electron microscopes and other advanced spectroscopic techniques. Finally, an electrode for supercapacitor based on the N-graphene-metal-oxide(sulfide) hybrid nanostructures is developed with promising specific capacitances (∼273 F.g−1 at 0.5 A.g−1). The described chemically engineered process is one of the fastest approaches reported for designing the high-quality hybrid nanostructures produced at a high-yield, and as such, is expected to provide a high impact on the design of electrode materials for sustainable energy storage systems.