Trimetallic metal–organic framework nanosheets as nanozymes for the electrochemical sensing of H2O2

A variety of two-dimensional (2D) metal–organic framework (MOF) nanosheets have been discovered with excellent peroxidase-like activity due to their merits of accessible active sites and large surface area. However, few methods can be used for the large-amount production of 2D MOF nanosheets. Herein, we report a simple room temperature solution phase method for the high-yield synthesis of 2D trimetallic MOF nanosheets with three kinds of metal ions as ligands. The as-synthesized NiCoM (M = Cu, Fe, and Zn) nanosheets showed markedly enhanced electrochemical activity due to the synergistic effect. Among these obtained nanosheets, NiCoFe showed the highest electrocatalytic activity, demonstrating that Fe played a dominant role in determining the activities of nanozymes. As a proof-of-concept application, 2D NiCoFe nanosheets are used as modified materials for the electrochemical detection of H 2 O 2 . The results showed that the fabricated sensor can detect  hydrogen peroxide (H 2 O 2 ) with a detection range of 5.0 μM − 15 mM, a detection limit of 2.1 μM, excellent selectivity and stability. Moreover, the fabricated NiCoFe nanosheet-based electrochemical sensor can be used for the detection of H 2 O 2 in serum samples. Our work provides a scalable method for the large-scale synthesis of 2D trimetallic MOF nanosheets as enhanced nanozymes for various applications.