▎ 摘　　要

NOVELTY - Mercury-induced two-dimensional graphene oxide stabilized silver sulfide nano-mimetic enzyme prepared by strongly coordinating between empty d-orbitals of silver in nano-silver sulfide and lone pair electrons on the oxygen-rich atoms of graphene oxide, and uniformly coordinating and adsorbing the nano-silver sulfide on the nano-graphene oxide substrate under the condition of ultrasonic dispersion, and constructing two-dimensional graphene oxide stabilized silver sulfide, and silver sulfide-graphene oxide, is claimed. USE - The nano-mimetic enzyme is useful for naked-eye sensor visual detection of heavy metal mercury in environmental samples or colorimetric detection of mercury content (claimed). ADVANTAGE - The silver sulfide-graphene oxide/TMB reaction system: has no nano-enzyme activity, high-efficiency oxidation mimic enzyme activity in the presence of mercury, specific and selective spectral response to heavy metal mercury; and is accompanied by a colorless to blue enhancement effect of visibility, Michaelis constant (Km) and the maximum initial rate (Vmax) of the enzyme catalysis to 0.10 mM and 3.94x 10-8 M/s. The metal mercury has a strong coordination effect with S element, which can extract S element from nano-silver sulfide and restore the strong catalytic effect of nano-silver itself and can be oxidized colorimetric substrate 3,32,5,52-tetramethylbenzidine in the presence of oxygen to produce blue oxTMB. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: (1) preparing the mercury-induced two-dimensional graphene oxide stabilized silver sulfide nano-mimetic enzyme comprising (1) adding silver nitrate in a flask, adding water and graphene oxide in sequence, (2) adding sodium sulfide aqueous solution dropwisely under ultrasonic conditions, and reacting at room temperature, and (3) centrifuging the obtained crude product, thoroughly washing with deionized water, and vacuum-drying to obtain two-dimensional graphene oxide stabilized silver sulfide; (2) use method for two-dimensional graphene oxide stabilized silver sulfide nano-mimetic enzyme comprising (i) preparing silver sulfide-graphene oxide standard solution and mercury standard solution, (ii) preparing environment sample, taking a random amount of water samples from different environments and filtering for three times through a 4.5 mu m microporous filter membrane to remove suspended solids, and (iii) carrying out visual detection of the heavy metal mercury in the sample by naked-eye sensing, pipetting 600 mu l of 0.1 mg/ml silver sulfide-graphene oxide standard solution into the centrifuge tube, adding 200 mu l of 1.5 mM 3,32,5,52-tetramethylbenzidine (TMB) and different volumes of 4 mmol/l mercury standard solution or sample to be tested, diluting to 3 ml disodium hydrogen phosphate-citric acid buffer solution with pH of 4, mixing well, adding at room temperature for 30 minutes, measuring the absorption spectrum of the system, and observing the color change of the solution; and (3) use method of two-dimensional graphene oxide stabilized silver sulfide nano-mimetic enzyme comprising providing 600 mu l of 0.1 mg/ml silver sulfide-graphene oxide standard solution, adding different volumes of 4 mmol/l mercury ion standard solution or test sample and 200 mu l of 1.5 mM 3,32,5,52-tetramethylbenzidine, diluting the volume to 3 ml disodium hydrogen phosphate-citric acid buffer solution with a pH 4, mixing well, and allowing to stand at room temperature for 30 minutes, measuring the absorption spectrum of the system, and bringing the absorption intensity value into lambda A652=0.00822+0.00576cHg2+(R2=0.968), where the linear range is 0-180x 10-8 M cHg2+, and calculating the concentration of mercury ion in the sample to be tested.