Graphene and MXene Nanomaterials: Toward High-Performance Electromagnetic Wave Absorption in Gigahertz Band Range

Carbon materials, with their diverse allotropes, have played significant roles in our daily life and the development of material science. Following 0D C60 and 1D carbon nanotube, 2D graphene materi...

3D Graphene Materials: From Understanding to Design and Synthesis Control.

https://rua.ua.es/dspace/bitstream/10045/107163/2/Quilez-Bermejo_etal_2020_Carbon_accepted.pdf

Metal-free heteroatom-doped carbon-based catalysts for ORR: A critical assessment about the role of heteroatoms

Air filtration materials (AFMs) have gradually become a research hotspot on account of the increasing attention paid to the global air quality problem. However, most AFMs cannot balance the contrad...

Multistructured Electrospun Nanofibers for Air Filtration: A Review.

Three-dimensional (3D) graphene materials, consisting of unstacked two-dimensional (2D) graphene sheets serving as building blocks, have been widely reported in recent years. Various synthetic methods have been employed to prepare graphene materials with diverse 3D architectures, which show potential in a wide range of applications such as energy and environmental technologies. In particular, application of 3D graphene-based materials in metal (Li, Na, K, Mg, Al)-ion battery (MIB) systems has been reported often in recent years. However, the critical roles of 3D graphene materials in MIB systems have not been comprehensively discussed. Herein, we first summarize the configurations and preparation of 3D graphene materials. Second, we illustrate the metal-ion storage mechanisms in graphene layers, i.e. intercalation and adsorption. Third, we emphasize the superior functionalities of 3D graphene architectures as supporting and encapsulated materials in MIB applications. Last, we discuss the merits and drawbacks of various 3D graphene architectures in MIB systems. We aim to present a comprehensive understanding of 3D graphene materials and guide directions for future MIB design.

Advances in three-dimensional graphene-based materials : configurations, preparation and application in secondary metal (Li, Na, K, Mg, Al)-ion batteries

3D assembly of graphene sheets (GSs) is important for preserving the merits of the single-atomic-layered structure. Simultaneously, vertical growth of GSs has long been a challenge for thermal chemical vapor deposition (CVD). Here, vertical growth of the GSs is achieved in a thermal CVD reactor and a novel 3D graphene structure, 3D graphene fibers (3DGFs), is developed. The 3DGFs are prepared by carbonizing electrospun polyacrylonitrile fibers in NH3 and subsequently in situ growing the radially oriented GSs using thermal CVD. The GSs on the 3DGFs are densely arranged and interconnected with the edges fully exposed on the surface, resulting in high performances in multiple aspects such as electrical conductivity (3.4 × 104 -1.2 × 105 S m-1 ), electromagnetic shielding (60 932 dB cm2 g-1 ), and superhydrophobicity and superoleophilicity, which are far superior to the existing 3D graphene materials. With the extraordinary properties along with the easy scalability of the simple thermal CVD, the novel 3DGFs are highly promising for many applications such as high-strength and conducting composites, flexible conductors, electromagnetic shielding, energy storage, catalysis, and separation and purification. Furthermore, this strategy can be widely used to grow the vertical GSs on many other substrates by thermal CVD.

3D Graphene Fibers Grown by Thermal Chemical Vapor Deposition

To replace the noble-metal Pt catalysts for oxygen reduction reaction (ORR), developing efficient and earth-abundant electrocatalysts is of great importance. Both the morphology and composition engineering of graphene could effectively modify the electronic structure to optimize its electrocatalytic performance for ORR. Here, we report an effective method to dope carbon materials with N, by which the N doping concentration and form could be well controlled. We first grow 3D graphene fibers (3DGFs) by thermal chemical vapor deposition, which are then treated with acid or heated in air and heated in NH3 in succession, obtaining N,O-codoped 3DGFs. The codoped 3DGFs exhibit outstanding electrocatalytic performance toward ORR with onset potential of 1.01 V, half-wave potential of 0.883 V, long-term operation stability with 90% current retention after 50 h, and a good methanol tolerance in alkaline solutions, which are superior to 20 wt% Pt/C catalyst and other reported advanced metal-free catalysts. The excellent catalytic performance of the 3DGFs probably arises from the synergic effect of the morphology and composition engineering, e.g., the edges and doping, especially the pyridine N. The present work is expected to open up new approach to design outstanding metal-free carbon-based electrocatalysts for ORR.

Yihui Ma

Papers

3D Graphene Fibers Grown by Thermal Chemical Vapor Deposition

N,O-codoped 3D graphene fibers with densely arranged sharp edges as highly efficient electrocatalyst for oxygen reduction reaction