▎ 摘　　要

NOVELTY - Preparing surface functionalized graphene material involves freeze-drying the graphene oxide raw material to obtain graphene oxide powder, dissolving the graphene oxide powder in deionized water, and ultrasonically oscillating the formed mixed solution, where, in each mixture, the volume of deionized water is 80 mL, and the mass of the graphene oxide powder is 40 mg. 2 mmole Of thiourea or urea is added to each mixture, to form second mixture, and the second mixture is stirred to completely dissolve the thiourea or urea. The mixed solution is subjected to hydrothermal reaction. Then, mixture is cooled to room temperature, and then centrifuged and washed with water to obtain third mixture, and then the third mixture is vacuum dried to obtain sulfur-doped graphene material or nitrogen-doped graphene material. USE - Method for preparing surface functionalized graphene material for use in electrochemical sensor (all claimed). ADVANTAGE - The method utilizes thiourea and urea to perform surface controllable functionalization of graphene oxide, so that the surface of the graphene oxide is introduced into a functional group, and the complexation of the functionalized graphene material with the mercury ion in the water environment is increased. It improves the electrochemical response to mercury ions. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) a method for detecting trace mercury ions in an aqueous environment, which involves preparing a certain amount of sulfur-doped graphene material or nitrogen-doped graphene material by the method for preparing a surface functionalized graphene material, dissolving the sulfur-doped graphene material or the nitrogen-doped graphene material in dimethylformamide, and forming a mixed liquid four, and then taking up the suspension of the mixed liquid four and dispensing on the glassy carbon electrode, finally the air-modified glassy carbon electrode, detecting trace mercury ions in the water environment by using a glassy carbon electrode after air drying, and through the external standard method, increasing the concentration of mercury ions in the water environment from the low concentration, measuring a series of electrochemical response values, and drawing the corresponding volt-ampere curve; and (2) an electrochemical sensor to detect mercury ions, which comprises glassy carbon electrode, and surface-functionalized graphene material which is provided on the glassy carbon electrode.