▎ 摘　　要

NOVELTY - Preparing nitrogen-doped graphene ink comprises e.g. (i) adding the 0.02-0.06 g/ml graphite powder into concentrated sulfuric acid, mixing fully, mixing graphite and potassium permanganate, carrying out gradient heating reaction, cooling, washing the mixture using de-ionized water to neutral, pouring the supernatant, centrifuging collecting and freeze drying to obtain the graphene oxide powder; (ii) dissolving the graphene oxide in water, processing ultrasonically to obtain dispersion liquid, adding ammonium carbonate, stirring and performing hydrothermal reaction to obtain nitrogen-doped graphene; and (iii) adding the nitrogen-doped graphene into water, performing ultrasonic treatment, adding the surfactant sodium deoxycholate into the system for many times, carrying out total ultrasonic processing for 12-300 hours, finishing ultrasonic condition, allowing to stand for 3 hours and collecting the upper clear liquid. USE - The nitrogen-doped graphene ink is useful in uniform droplet jet printing platform. ADVANTAGE - The method: can oxidize graphene oxide with higher oxygen content; and produces obtain a large sheet of stable and dispersed nitrogen-doped graphene ink with the sheet size of 800-2000 nm and the thickness is 12nm, has stable dispersion and micron-level flake spreading effect. DETAILED DESCRIPTION - Preparing nitrogen-doped graphene ink comprises (i) adding the 0.02-0.06 g/ml graphite powder into concentrated sulfuric acid, mixing fully, mixing graphite and potassium permanganate at ratio of 1:3-1:10, carrying out gradient heating reaction, cooling to room temperature to obtain the mixture, where the gradient heating the temperature gradient is set to 1- 5, the temperature range is 0-70 degrees C, the total reaction time 4-100 hours, washing the mixture using de-ionized water to neutral, pouring the supernatant, completing the process with a centrifuge, collecting the bottom slurry and freeze drying after ultrasonic processing to obtain the graphene oxide powder; (ii) dissolving the graphene oxide in water, processing ultrasonically to obtain dispersion liquid, adding ammonium carbonate into the dispersion liquid, stirring fully, where the mass ratio of the graphene oxide to the ammonium carbonate is 1:1-500, introducing the dispersion liquid added with ammonium carbonate into a hydrothermal reaction kettle, sealing the reaction kettle into an oven and performing hydrothermal reaction at 70-250 degrees C to obtain nitrogen-doped graphene; and (iii) adding the nitrogen-doped graphene into water to prepare 1-5 mg/ml dispersion liquid, performing ultrasonic treatment, adding the surfactant sodium deoxycholate into the system for many times, where the ultrasonic treatment comprising ultrasonic power is 30-240 W power alternately ultrasonic, where each section of ultrasonic time is 0.4-2 hours, the ratio of the high and low power ultrasonic time is 2:1-5: 1, carrying out total ultrasonic processing for 12-300 hours, finishing ultrasonic condition, allowing to stand for 3 hours and collecting the upper clear liquid. DESCRIPTION OF DRAWING(S) - The drawing shows a schematic representation of the preparing nitrogen-doped graphene ink. (Drawing includes non-English language text).