Embedded ZnO nanorod in ZIF-8 as a high-efficiency core–shell structural electrocatalyst for subnanomole level sensing of diethylstilbestrol

Abstract

In view of the core–shell nanocomposites can complement the functions of the core and shell components, we here demonstrate a facile self-template strategy for synthesizing a one-dimensional rod-like hierarchical ZnO@ZIF-8 core–shell structure composed of a stabilized core and an active shell. The ZnO nanorods not only served as the template, but also as source of Zn ions for the in situ formation of zeolitic imidazolate framework-8 (ZIF-8) crystal shell, and the well-stabilized ZnO core preserved its own nature during the growth of the ZIF-8 shell. Furthermore, a sensing platform using ZnO@ZIF-8 as electrocatalyst was developed, which demonstrated salient electrocatalytic activity for diethylstilbestrol (DES) oxidation. The concentration of DES was directly proportional to its anodic peak current in the range of 2 nmol/L to 2 µmol/L, and ultralow detection limit of 0.73 nmol/L ( S/ N = 3) was achieved. The proposed method also gave excellent selectivity, reproducibility, and stability, showing promising analytical performance for the measurement of DES in food samples of animal origin.