3D graphene foam is a material composed of graphene sheets that are interconnected in a three-dimensional structure, forming a porous foam-like material. It is synthesized using chemical vapor deposition (CVD) with a template-assisted method, which results in the growth of an interconnected 3D porous network of multilayer graphene sheets.
How is 3D Graphene Foam Synthesized?
The template-assisted chemical vapor deposition (CVD) method is commonly used to create 3D interconnected graphene networks. This method merges the 3D structure of a template with graphene’s unique properties, resulting in porous, lightweight materials with superior transport and mechanical attributes. The synthesis process for 3D graphene mirrors that of 2D graphene, where a carbon precursor decomposes on growing substrates in a hydrogen-argon mix. The substrate, which can be metallic or nonmetallic, acts as both a catalyst for decomposition and a template for the graphene structure.¹
Carbon sources for this process can be gaseous, liquid, or solid. During CVD, these sources decompose at temperatures between 900-1050°C in a hydrogen and argon atmosphere, depositing graphene layers on the substrate. The overall procedure includes template cleaning, hydrogenation or oxidation, CVD growth, and template etching to produce 3D graphene foam.¹
The growth mechanism on porous structures is either surface-mediated self-limited growth for 3D graphene monolayers or a segregation mechanism for multilayers. Copper is preferred for single-layer graphene due to its low carbon solubility, while nickel is preferred for multilayer graphene due to its high carbon solubility. The template foam’s key features include pore size, interconnectivity, shape, and substrate type.
Various catalysts and synthesis conditions are used to control graphene layers and foam porosity. Substrate types range from foams, films, and nanopowders to metals, metal oxides, metal salts, and seashells. Commercial nickel foam, due to its cost-effectiveness and varied sizes/pore densities, is the most popular template. Graphene forms a continuous network on the Ni foam surface, maintaining its 3D structure and porosity even after the scaffold is etched away.¹
Recent Research into Multilayer Graphene Foam
Graphene-coated nickel foam’s large surface area, porosity, and high electrical conductivity has made it popular as an electrode material for a variety of catalytic reactions. As an example, graphene-coated nickel foam electrodes have demonstrated promising results in the mineralization of pharmaceutical and personal care products in previously-treated wastewater.²
Free-standing graphene foam can be obtained by etching away the underlying nickel template following graphene growth. Free-standing graphene foam possesses unique attributes – such as Interconnected microporosity, nanoroughness, high electrical conductivity, biocompatibility, ultralow density, broad surface modification potential, and tunable stiffness – that make it a compelling scaffold biomaterial to assist in stem cell growth and differentiation. Free-standing CVD graphene foam has been thoroughly investigated in academic research as a scaffold biomaterial, with positive outcomes in several tissue engineering and 3D cell culture studies.³
Intensive research into the commercialization of 3D graphene foam is ongoing, but many exciting prospects exist beyond the fields mentioned above – including the use of multilayer graphene in pressure sensing and as low density mechanical supports.
Interested in learning more? Refer to our page on 3D graphene foams for more details.
References and further reading:
¹ Banciu CA, Nastase F, Istrate AI, Veca LM. 3D Graphene Foam by Chemical Vapor Deposition: Synthesis, Properties, and Energy-Related Applications. Molecules. 2022 Jun 6;27(11):3634. doi:
10.3390/molecules27113634. PMID: 35684569; PMCID: PMC9181857.
² Srinivasan, R., & Nambi, I. M. (2022). An electro-peroxone-based multi-pronged strategy for the treatment of ibuprofen and an emerging pharmaceutical wastewater using a novel graphene-coated nickel foam electrode. Chemical Engineering Journal, 450, 137618.
³ Bellet, P., Gasparotto, M., Pressi, S., Fortunato, A., Scapin, G., Mba, M., Menna, E., & Filippini, F.(2021). Graphene-Based Scaffolds for Regenerative Medicine. Nanomaterials (Basel, Switzerland), 11(2), 404. https://doi.org/10.3390/nano11020404