Methods for making a multilevel core-shell structure having a core/graphene-based shell structure are described. A method for making a core/graphene-based shell structure can include obtaining a composition that includes core nano- or microstructures and graphene-based structures having at least a portion of a surface coated with a curable organic material, where the core nano- or microstructures and graphene-based structures are dispersed throughout the composition and subjecting the composition to conditions that cure the organic material and allow the graphene-based structures to self-assemble around the core nano- or microstructures to produce a core/graphene-based shell structure that has a graphene-based shell encompassing a core nano- or microstructure.

Provided herein are carbon-based oxide (CBO) materials and reduced carbon-based oxide (rCBO) materials, fabrication processes, and devices with improved performance and a high throughput. In some embodiments, the present disclosure provides materials and methods for synthesizing CBO and rCBO materials. Such methods avoid the shortcomings of current synthesizing methods to facilitate facile, high-throughput production of CBO and rCBO materials.

Photoreduction of graphene oxide, by UV-generated ketyl radicals, to graphene. The photoreduction is versatile and can be carried out in solution, solid-state, and even in polymer composites. Reduction of graphene oxide can take place in various polymer matrixes. Methods for producing graphene-supported metal nanoparticles by photoreduction. Graphene oxide and a metal nanoparticle precursor are simultaneously reduced by the action of photogenerated ketyl radicals. Photoreduction is performed on polymer composite films in one embodiment.

Disclosed are a graphene-supported noble-metal composite powder, a preparation method thereof, and a Schottky device. In the disclosure, graphene oxide and a noble metal precursor, as raw materials, are subjected to a hydrothermal reduction reaction to prepare the composite powder. In the process of the hydrothermal reduction reaction, graphene oxide and noble metal ions can be simultaneously reduced, and the formed noble metal nanoparticles are uniformly distributed on the surface and between layers of graphene, which effectively suppresses agglomeration of graphene, thereby fully exerting the electrical conductivity of graphene.

Disclosed are a graphene-supported noble-metal composite powder, a preparation method thereof, and a Schottky device. In the disclosure, graphene oxide and a noble metal precursor, as raw materials, are subjected to a hydrothermal reduction reaction to prepare the composite powder. In the process of the hydrothermal reduction reaction, graphene oxide and noble metal ions can be simultaneously reduced, and the formed noble metal nanoparticles are uniformly distributed on the surface and between layers of graphene, which effectively suppresses agglomeration of graphene, thereby fully exerting the electrical conductivity of graphene.

Method for making a liquid foam from graphene. The method includes preparing an aqueous dispersion of graphene oxide and adding a water miscible compound to the aqueous dispersion to produce a mixture including a modified form of graphene oxide. A second immiscible fluid (a gas or a liquid) with or without a surfactant are added to the mixture and agitated to form a fluid/water composite wherein the modified form of graphene oxide aggregates at the interfaces between the fluid and water to form either a closed or open cell foam. The modified form of graphene oxide is the foaming agent.

A super-flexible high thermal conductive graphene film and a preparation method thereof are provided. The graphene film is obtained from ultra large homogeneous graphene sheets through processes of solution film-forming, chemical reduction, high temperature reduction, high pressure suppression and so on. The graphene film has a density in a range of 1.93 to 2.11 g/cm.sup.3, is formed by overlapping planar oriented graphene sheets with an average size of more than 100 μm with each other through π-π conjugate action, and comprises 1 to 4 layers of graphene sheets which have few defects. The graphene film can be repeatedly bent for 1200 times or more, with elongation at break of 12-18%, electric conductivity of 8000-10600 S/cm, thermal conductivity of 1800-2600 W/mK, and can be used as a highly flexible thermal conductive device.

A super-flexible high thermal conductive graphene film and a preparation method thereof are provided. The graphene film is obtained from ultra large homogeneous graphene sheets through processes of solution film-forming, chemical reduction, high temperature reduction, high pressure suppression and so on. The graphene film has a density in a range of 1.93 to 2.11 g/cm.sup.3, is formed by overlapping planar oriented graphene sheets with an average size of more than 100 μm with each other through π-π conjugate action, and comprises 1 to 4 layers of graphene sheets which have few defects. The graphene film can be repeatedly bent for 1200 times or more, with elongation at break of 12-18%, electric conductivity of 8000-10600 S/cm, thermal conductivity of 1800-2600 W/mK, and can be used as a highly flexible thermal conductive device.

Methods of producing graphene nanoplatelets by exposing graphite to a medium to form a dispersion of graphite in the medium. In some embodiments, the exposing results in formation of graphene nanoplatelets from the graphite. In some embodiments, the medium includes the following components: (a) an acid; (b) a dehydrating agent; and (c) an oxidizing agent. In some embodiments, the methods of the present disclosure result in the formation of graphene nanoplatelets at a yield of more than 90%. In some embodiments, the methods of the present disclosure result in the formation of graphene nanoplatelets in bulk quantities that are more than about a 1 kg of graphene nanoplatelets. Additional embodiments of the present disclosure pertains to the formed graphene nanoplatelets. In some embodiments, the graphene nanoplatelets include a plurality of layers, such as from about 1 layer to about 100 layers.

A process and system for the electrochemical production of graphene, graphene oxide, graphene quantum dots, graphene/graphene oxide metal composites, graphene/graphene oxide coated substrates and graphene/graphene oxide metal composite coated substrates in a single step process involving no secondary purifications utilizes an electrochemical cell containing electrodes with variable gaps including a zero gap, containing an anode electrode including graphite, a cathode electrode including electrically conductive material with an electrolyte-free electrochemical bath including water and an organic liquid that produces joule heating along with oxygen embrittlement.