▎ 摘　　要

NOVELTY - Method for preparing a graphene-coated transition metal carbide nanocapsule involves (i) placing 20-200 g transition metal block on an anode of a direct current arc hydrogen plasma device, introducing hydrogen, an inert gas and a carbon-containing element gas, where the volume of the inert gas is 0-9 times hydrogen, the volume of the carbon-containing element gas is 0.005-0.5 times hydrogen, and the total air pressure of the reaction chamber is maintained at 0.005 Pa to 9.5x 104 Pa and (ii) turning on power supply to form a stable arc, evaporating the transition metal block, controlling the arc reaction time to be 5-15 minutes, cooling the reaction product to room temperature and introducing a small amount of air for passivation treatment. USE - The method is useful for preparing a graphene-coated transition metal carbide nanocapsule used in microwave catalysis. ADVANTAGE - The method adopts simple process, can be prepared on a large scale, can control morphology by adjusting the atmosphere, provides pure product and has short reaction time. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for use of the graphene-coated transition metal carbide nanocapsule in microwave catalysis by (1a) uniformly dispersing the graphene-coated transition metal carbide nanocapsule in a solution containing contaminants, placing in a three-necked flask to prepare a microwave reaction suspension, where the concentration of the graphene-coated transition metal carbide nanocapsule is 1-5000 mg/l and the concentration of the contaminants is 0.1-1000 mmol/l and (ii) connecting a suspension liquid prepared in step (1a) with stirring and a cooling device, placing in a microwave reactor to prepare a microwave reaction device, irradiating the suspension liquid by microwave electromagnetic waves with set power and frequency and testing the microwave catalytic degradation performance of the catalyst on the contaminants after irradiation for a period of time, where the microwave power is 200-1200 W, the microwave frequency is 1-20 GHz and the irradiation time is 0.01-180 minutes.