Electrochemical behavior of horseradish peroxidase on WS2 nanosheet‐modified electrode and electrocatalytic investigation

Abstract

In this paper, a WS2 nanosheet was modified on the surface of a carbon ionic liquid electrode (CILE), and horseradish peroxidase (HRP) was further fixed on the electrode with a Nafion film. Direct electrochemistry and bioelectrocatalysis of HRP incorporated on the modified electrode were investigated in detail. On Nafion/HRP/WS2/CILE, a pair of well‐defined quasi‐reversible redox peaks appeared on the cyclic voltammogram, indicating that the presence of the WS2 nanosheet on the electrode surface could provide a specific interface with large surface area for HRP and its direct electron transfer rate was greatly enhanced. The formal potential (E0) obtained was –0.179 V, which was the typical feature of heme Fe(III)/Fe(II) in HRP. The electron transfer coefficient (α) and the heterogeneous electron transfer rate constant (ks) of HRP were calculated as 0.44 and 1.01 s–1, respectively. This HRP‐modified electrode showed excellent electrocatalytic activity for the reduction of trichloroacetic acid and NaNO2 with a wide linear range and low detection limit. Real samples were detected by this proposed method, indicating the successful fabrication of a new third‐generation electrochemical enzyme sensor utilizing the WS2 nanosheet.