A method for preparing fluorescent carbon quantum dots by using gas-liquid two-phase plasma is provided, which relates to the field of fluorescent carbon quantum technology. On the basis of liquid phase plasma, an inert gas is introduced to generate plasma by a gas-liquid two-phase discharge method. The introduction of inert gas facilitates the formation of discharge channels, reduces the difficulty of product synthesis, improves mass transfer rates of active particles, helps to improve synthesis rates of carbon nano-products, increases discharge contact area and enhances discharge stability. A high reaction efficiency and a short time consumption can be realized. A pulsed power supply is adopted for discharge, which has lower energy consumption compared with the direct current discharge. Moreover, the process is simple, raw materials are easy to obtain, and there is no need for catalysts, strong oxidants or strong corrosives, so the purity of the product maybe higher.

A method for synthesizing fluorescent carbon quantum dots (CQDs) and nitrogen-phosphorus co-doped fluorescent CQDs and applications are provided. Firstly, a mixture of leaf powder and deionized water is subjected to hydrothermal reaction at 200-240° C. to obtain a product A, followed by removing by-products in it and drying to obtain fluorescent CQDs; nitrogen-phosphorus co-doped fluorescent CQDs are obtained by replacing the product A with a product B and treating the product B in a same way as the product A, where product B is obtained as follows: a mixed system of leaf powder, urea phosphate and deionized water is subjected to hydrothermal reaction at 200-240° C. with a mass ratio of urea phosphate to leaf powder as less than or equal to 0.2 to obtain the product B.

A method for synthesizing fluorescent carbon quantum dots (CQDs) and nitrogen-phosphorus co-doped fluorescent CQDs and applications are provided. Firstly, a mixture of leaf powder and deionized water is subjected to hydrothermal reaction at 200-240° C. to obtain a product A, followed by removing by-products in it and drying to obtain fluorescent CQDs; nitrogen-phosphorus co-doped fluorescent CQDs are obtained by replacing the product A with a product B and treating the product B in a same way as the product A, where product B is obtained as follows: a mixed system of leaf powder, urea phosphate and deionized water is subjected to hydrothermal reaction at 200-240° C. with a mass ratio of urea phosphate to leaf powder as less than or equal to 0.2 to obtain the product B.

This application describes a process for the preparation of carbon-coated particles, where the particles comprise an electrochemically active material. The process comprises the steps of emulsion polymerization, drying and thermally treating the polymer to obtain a nano-layer of carbon on the particles, where the carbon layer comprises fibers and nitrogen-containing polyaromatics have a graphene-like structure. The application also further relates to the particles produced by the method as well as to electrode materials, electrodes and electrochemical cells comprising the particles.

This application describes a process for the preparation of carbon-coated particles, where the particles comprise an electrochemically active material. The process comprises the steps of emulsion polymerization, drying and thermally treating the polymer to obtain a nano-layer of carbon on the particles, where the carbon layer comprises fibers and nitrogen-containing polyaromatics have a graphene-like structure. The application also further relates to the particles produced by the method as well as to electrode materials, electrodes and electrochemical cells comprising the particles.

A method of fabricating polyacrylonitrile (PACN) nanostructured carbon superstructure shapes is provided that includes forming a PACN polymer superstructure shape by using as a monomer, an initiator, and a solvent or incorporation of a different co-monomer for free radical polymerization, and converting the PACN polymer superstructure shape to a nanostructured carbon superstructure analogue using stabilization and carbonization of the PACN polymer superstructure shape, where the stabilization includes heating the PACN polymer superstructure shape to a temperature that is adequate to form a stabilization reaction, where the carbonization includes using a heat treatment.

A method of fabricating polyacrylonitrile (PACN) nanostructured carbon superstructure shapes is provided that includes forming a PACN polymer superstructure shape by using as a monomer, an initiator, and a solvent or incorporation of a different co-monomer for free radical polymerization, and converting the PACN polymer superstructure shape to a nanostructured carbon superstructure analogue using stabilization and carbonization of the PACN polymer superstructure shape, where the stabilization includes heating the PACN polymer superstructure shape to a temperature that is adequate to form a stabilization reaction, where the carbonization includes using a heat treatment.

A method for modifying surface wettability of a surface of a solid substrate may include contacting the surface of the solid substrate with a brine solution containing carbon nanodots. The carbon nanodots may have carbon, oxygen, nitrogen, and hydrogen as constituent elements and may include one or more functional groups disposed at outer surfaces of the carbon nanodots. The brine solution has a salinity of greater than 30,000 TDS. A concentration of carbon nanodots in the brine solution is less than or equal to 500 ppmw. Contacting the solid substrate with the brine solution comprising the carbon nanodots is characterized by a contact duration, a contact volume, or both, that is sufficient to reduce the oil wettability of the surface of the solid substrate by at least 15%, as defined by a contact angle of a crude oil droplet contacted with the surface of the solid substrate.

A method for modifying surface wettability of a surface of a solid substrate may include contacting the surface of the solid substrate with a brine solution containing carbon nanodots. The carbon nanodots may have carbon, oxygen, nitrogen, and hydrogen as constituent elements and may include one or more functional groups disposed at outer surfaces of the carbon nanodots. The brine solution has a salinity of greater than 30,000 TDS. A concentration of carbon nanodots in the brine solution is less than or equal to 500 ppmw. Contacting the solid substrate with the brine solution comprising the carbon nanodots is characterized by a contact duration, a contact volume, or both, that is sufficient to reduce the oil wettability of the surface of the solid substrate by at least 15%, as defined by a contact angle of a crude oil droplet contacted with the surface of the solid substrate.

A method of forming a battery electrode by forming, on a first substrate, a polymer template comprising interconnected polymer fibers, forming, on the polymer template, a carbon coating to form a carbon-coated polymer template, removing the carbon-coated polymer template from the first substrate, subsequent to removing the carbon-coated polymer template from the first substrate, removing the polymer template from the carbon coating, and disposing the carbon coating on a second substrate. A solid electrolyte interphase layer (SEI) comprising the carbon coating produced via the method, a battery electrode comprising such an SEI layer, and a battery comprising such a battery electrode are also provided.