▎ 摘　　要

NOVELTY - Preparing graphene comprises e.g. (i) washing tin with water at 40-100 degrees C, then washing with organic solvent, and then blown drying, (ii) cleaning tin and solid carbon source, placing in the reactor, placing reactor in tube furnace, and then introducing argon gas into the tube furnace and the reactor, (iii) maintaining argon atmosphere, introducing hydrogen into reactor, and then maintaining at constant temperature of 20-60 minutes, (iv) reducing flow rate of argon gas to 50-100 ml/minutes, close the valve at the end of the tube furnace within half minute, pressing 1/5-1/3 of the liquid tin in the reactor out of the reactor to the receiving vessel, then open the valve to balance the pressure in the reactor, and (v) continue to pass argon gas at 50-100 ml/minutes, stop heating, after temperature drops to room temperature, turning off argon and hydrogen, and taking out receiving container, washing and separating the mixed product of metal tin and graphene in the receiving container. USE - The method is useful for preparing graphene. ADVANTAGE - The graphene does not use toxic and harmful dangerous chemicals, and the method replaces gaseous carbon source with solid carbon source which reduces the process difficulty. DETAILED DESCRIPTION - Preparing graphene comprises (i) washing tin with water at 40-100 degrees C, then washing with organic solvent, and then blown drying, (ii) cleaning tin and solid carbon source, placing in the reactor based on total mass of the carbon of 0.1-1 wt.%, placing reactor in tube furnace, and then introducing argon gas into the tube furnace and the reactor, and where flow rate of argon gas is 500-1500 ml/minutes to exclude the air in the tube furnace and the reactor, and receiving container in the tube furnace, (iii) maintaining argon atmosphere, introducing hydrogen into the reactor at hydrogen flow rate of 50-200 ml/minutes, increasing at a rate of 5-10 degrees C/minutes, maintaining final temperature at 1000-2000 degrees C, and then maintaining at constant temperature of 20-60 minutes, (iv) reducing flow rate of argon gas to 50-100 ml/minutes, close the valve at the end of the tube furnace within half minute, pressing 1/5-1/3 of the liquid tin in the reactor out of the reactor to the receiving vessel, then open the valve to balance the pressure in the reactor so that the liquid tin in the reactor is no longer pressed out, and (v) continue to pass argon gas at 50-100 ml/minutes, stop heating, after temperature drops to room temperature, turning off argon and hydrogen, and taking out receiving container, washing and separating the mixed product of metal tin and graphene in the receiving container.