▎ 摘　　要

Palladium nanoparticles with diameter of around 5-10 nm supported on poly (diallyldimethylammonium chloride) (PDDA)-functionalized graphene composites were prepared by a simple chemical method. As prepared nanocomposites were characterized by transmission electron microscopy (TEM), x-ray diffraction (XRD), ultraviolet -visible spectrophotometry (UV-vis) and electrochemical techniques, which were clearly demonstrated that palladium nanoparticles were uniformly dispersed on the graphene sheets. Based on the PDDA-Gr-Pd nanocomposites, a new voltammetric sensor was established and exhibited excellent electrocatalytic activity and fast electron transfer rate toward taxifolin. Under the optimal conditions, a lower detection limit of 1x10(-9) mol L-1 (S/N=3) and a wide linear detection range from 4x10(-8) to 1x10(-6) mol L-1 were achieved by square wave voltammetry (SWV). The proposed method was successfully applied for determination of taxifolin in fructus polygoni orientalis with well results.