Graphene’s success has shown that it is possible to create stable, single and few-atom-thick layers of van der Waals materials, and also that these materials can exhibit fascinating and technologically useful properties. Here we review the state-of-the-art of 2D materials beyond graphene. Initially, we will outline the different chemical classes of 2D materials and discuss the various strategies to prepare single-layer, few-layer, and multilayer assembly materials in solution, on substrates, and on the wafer scale. Additionally, we present an experimental guide for identifying and characterizing single-layer-thick materials, as well as outlining emerging techniques that yield both local and global information. We describe the differences that occur in the electronic structure between the bulk and the single layer and discuss various methods of tuning their electronic properties by manipulating the surface. Finally, we highlight the properties and advantages of single-, few-, and many-layer 2D materials in...

/pdf/progress-challenges-and-opportunities-in-two-dimensional-1sweg4hljr.pdf

Progress, Challenges, and Opportunities in Two-Dimensional Materials Beyond Graphene

Nitrogen-doped graphene (N-graphene) was synthesized by chemical vapor deposition of methane in the presence of ammonia. The resultant N-graphene was demonstrated to act as a metal-free electrode with a much better electrocatalytic activity, long-term operation stability, and tolerance to crossover effect than platinum for oxygen reduction via a four-electron pathway in alkaline fuel cells. To the best of our knowledge, this is the first report on the use of graphene and its derivatives as metal-free catalysts for oxygen reduction. The important role of N-doping to oxygen reduction reaction (ORR) can be applied to various carbon materials for the development of other metal-free efficient ORR catalysts for fuel cell applications, even new catalytic materials for applications beyond fuel cells.

/pdf/nitrogen-doped-graphene-as-efficient-metal-free-2c5sl934bm.pdf

Nitrogen-Doped Graphene as Efficient Metal-Free Electrocatalyst for Oxygen Reduction in Fuel Cells

Approaches, Derivatives and Applications Vasilios Georgakilas,† Michal Otyepka,‡ Athanasios B. Bourlinos,‡ Vimlesh Chandra, Namdong Kim, K. Christian Kemp, Pavel Hobza,‡,§,⊥ Radek Zboril,*,‡ and Kwang S. Kim* †Institute of Materials Science, NCSR “Demokritos”, Ag. Paraskevi Attikis, 15310 Athens, Greece ‡Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacky University Olomouc, 17. listopadu 12, 771 46 Olomouc, Czech Republic Center for Superfunctional Materials, Department of Chemistry, Pohang University of Science and Technology, San 31, Hyojadong, Namgu, Pohang 790-784, Korea Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v.v.i., Flemingovo naḿ. 2, 166 10 Prague 6, Czech Republic

Functionalization of Graphene: Covalent and Non-Covalent Approaches, Derivatives and Applications

Graphene based materials: Past, present and future

Nitrogen doping has been an effective way to tailor the properties of graphene and render its potential use for various applications. Three common bonding configurations are normally obtained when doping nitrogen into the graphene: pyridinic N, pyrrolic N, and graphitic N. This paper reviews nitrogen-doped graphene, including various synthesis methods to introduce N doping and various characterization techniques for the examination of various N bonding configurations. Potential applications of N-graphene are also reviewed on the basis of experimental and theoretical studies.

https://s3-eu-west-1.amazonaws.com/pfigshare-u-files/1431849/NitrogenReviewonRecentProgressinNitrogenDopedGrapheneSynthesisCharacterizationandItsPotentialApplications.pdf

Review on Recent Progress in Nitrogen-Doped Graphene: Synthesis, Characterization, and Its Potential Applications

By using two-stage, metal-catalyst-free chemical vapor deposition (CVD), it is demonstrated that high-quality polycrystalline graphene films can directly grow on silicon nitride substrates. The carrier mobility can reach about 1500 cm(2) V(-1) s(-1) , which is about three times the value of those grown on SiO(2) /Si substrates, and also is better than some examples of metal-catalyzed graphene, reflecting the good quality of the graphene lattice.

Two‐Stage Metal‐Catalyst‐Free Growth of High‐Quality Polycrystalline Graphene Films on Silicon Nitride Substrates

Here, we study hierarchy of graphene wrinkles induced by thermal strain engineering and demonstrate that the wrinkling hierarchy can be accounted for by the wrinklon theory. We derive an equation λ = (ky)0.5, explaining evolution of wrinkling wavelength λ with the distance to the edge y observed in our experiment by considering both bending energy and stretching energy of the graphene flakes. The prefactor k in the equation is determined to be about 55 nm. Our experimental result indicates that the classical membrane behavior of graphene persists down to about 100 nm of the wrinkling wavelength.

Hierarchy of graphene wrinkles induced by thermal strain engineering

Graphene is only one atom thick and becomes the ultimate thin film to explore membrane physics and mechanics. Here we study hierarchy of graphene wrinkles induced by thermal strain engineering and demonstrate that the wrinkling hierarchy can be accounted for by the wrinklon theory. We derive an equation {\lambda} = (ky)0.5 explaining evolution of wrinkling wavelength {\lambda} with the distance to the edge y observed in our experiment by considering both bending energy and stretching energy of the graphene flakes. The prefactor k in the equation is determined to be about 55 nm, which is independent of the size of the graphene flakes. Our experimental result indicates that the classical membrane behavior of graphene persists down to about 100 nm of the wrinkling wavelength.

Hierarchy of Graphene Wrinkles Induced by Thermal Strain Engineering

The invention discloses grapheme foam and a preparation method thereof. The grapheme foam provided by the invention is prepared by the method comprising the following steps: 1) putting a metal foam material into a vacuum tube type furnace, and calcining the metal foam material under non-oxidizing atmosphere; 2) depositing grapheme on the calcined metal foam material by adopting a chemical vapor deposition method; and 3) removing foam metal from the obtained grapheme modified metal foam material, cleaning the obtained foam material by using deionized water, ethanol and ether in turn, taking the foam material out and drying the foam material to obtain grapheme foam. The grapheme foam material has a three-dimensional hollow porous netlike structure, the grapheme is on the netlike wall, and the structural characteristic effectively prevents the agglomeration of the grapheme; and the grapheme foam material integrates the characteristics of a foam material and a conductive material, and has the advantages of ultra-low density, ultra-high surface area, high heat conduction, high temperature resistance, corrosion resistance and the like.

Grapheme foam and preparation method thereof

The invention discloses a method for preparing graphene. The method comprises the following steps of: after heating a substrate loaded with a copper metal layer to a bulk phase melting point and above the bulk phase melting point of copper in the flowing anaerobic and anhydrous atmosphere, introducing a carbon-containing compound into a system to perform chemical vapor deposition to obtain the graphene on the surface of the copper metal layer after the deposition. According to the method, the graphene with various shapes is prepared by introducing inert gases under a liquid state copper catalyst. The method is easy and convenient to operate and high in quality of products, and can be used for large-scale production. The shapes of the graphene can be regulated and controlled by regulating a concentration ratio of the inert gases to carbon-containing substances and hydrogen.

Gui Yu

Papers

Two‐Stage Metal‐Catalyst‐Free Growth of High‐Quality Polycrystalline Graphene Films on Silicon Nitride Substrates

Hierarchy of graphene wrinkles induced by thermal strain engineering

Hierarchy of Graphene Wrinkles Induced by Thermal Strain Engineering

Grapheme foam and preparation method thereof

Method for preparing graphene