▎ 摘　　要

NOVELTY - Preparing sulfur and nitrogen co-doped three-dimensional graphene/manganese sulfide composite material involves ultrasonically dispersing 30-60mg graphene oxide in 15mL water to obtain 2-4 mg/mL aqueous solution of graphene. The 0.5-1g thiourea and 0.05-0.12g manganese chloride are added to aqueous solution of graphene and uniformly stirring for 30 minutes. The solution is transferred to the reaction kettle and reaction kettle is placed in a muffle furnace. The temperature is raised to 120-200 degrees C for 6 to 24 hours. The graphene oxide in the reactor is transformed into graphene hydrogel. USE - Method for preparing sulfur and nitrogen co-doped three-dimensional graphene/manganese sulfide composite material used for electrocatalytic reduction of oxygen (claimed). ADVANTAGE - The method enables to prepare sulfur and nitrogen co-doped three-dimensional graphene/manganese sulfide composite material in simple manner that has high activity and high stability. DETAILED DESCRIPTION - Preparing sulfur and nitrogen co-doped three-dimensional graphene/manganese sulfide composite material involves ultrasonically dispersing 30-60mg graphene oxide in 15mL water to obtain 2-4 mg/mL aqueous solution of graphene. The 0.5-1g thiourea and 0.05-0.12g manganese chloride are added to aqueous solution of graphene and uniformly stirring for 30 minutes. The solution is transferred to the reaction kettle and reaction kettle is placed in a muffle furnace. The temperature is raised to 120-200 degrees C for 6 to 24 hours. The graphene oxide in the reactor is transformed into graphene hydrogel. The thermal reaction is carried out with manganese sulfide and thiourea is attached to the graphene hydrogel surface. The graphene hydrogels are freeze-dried for 24 hours and then the temperature is raised to 700 degrees C. The temperature is raised to 2 hours under argon atmosphere. The composite ultrasonic dispersion is ground and dispersed in certain volume of water to obtain uniform dispersion. The composite is tested by electrochemical workstation and rotating disk electrode. The glassy carbon electrode is modified with graphene/manganese sulfide composite material which is used as the working electrode. The platinum is used as the counter electrode and silver/silver chloride is used as the reference electrode. The solution used in the electrochemical test is potassium hydroxide solution. The solution is purged with nitrogen or oxygen for 30-50 minutes before electrochemical test. The material is subjected to a linear sweep voltammetry test to determine the oxygen reduction activity of the material by observing the oxygen reduction onset potential and the limiting current density. The material is tested for 10000s at constant potential of -0.4 Volt and cyclic voltammetry method is carried out to obtain final product. The properties of the composite are investigated against methanol.