▎ 摘　　要

Platinum nanoparticles were loaded onto the surface of poly (ethylene glycol) -modified graphene oxide (GO/PEG/Pt) via an in-situ reduction method. GO/PEG/Pt nanohybrids had excellent peroxidase-like activity in aqueous solution, and could catalyze H2O2 to produce center dot OH rapidly , thus making the chromogenic substrate 3 , 3' , 5 ,5'-tetramethylbenzidine hydrochloride (TMB center dot 2HCl) changed obviously and an absorption peak appeared at 652 nm in UV-Vis absorption spectrum. However, when the mercury ions (Hg2+) were introduced, Hg2+ was reduced to Hg-0 by Pt-0 and deposited on the surface of platinum nanoparticles to form platinum amalgam, which resulted in the occupation of surface-active sites of GO/PEG/Pt , the signal output of the system was inhibited, and the degree of inhibition varied linearly with Hg2+ concentration. Therefore , under the optimized experimental conditions, the visual colorimetric sensor was constructed to realize the sensitive analysis and real-time detection of Hg2+. The detection limit of spectral analysis was 3. 96 nmol/L , and the detection limit of naked eye was 10 nmol/L. The method was applied to determination of hg(2+) in tap water and lake water, and the recoveries were between 95. 5% and 108. 6%.