Facile, low-temperature synthesis of tungsten carbide (WC) flakes for the sensitive and selective electrocatalytic detection of dopamine in biological samples

Abstract

Transition metal carbides have shown a promising potential for use in electrochemical applications due to their excellent electronic conductivity, stability and electrocatalysis. Herein, we described a facile, low-temperature method for synthesizing tungsten carbide (WC) used as an electrode modifier to fabricate a highly active electrochemical sensor for the determination of dopamine (DA). The as-synthesized WC was characterized by transmission electron microscopy, elemental mapping, X-ray diffraction, X-ray photoelectron spectroscopy, and electrochemical impedance spectroscopy. TEM results reveal that WC appeared as a flake-like structure with an average particle size of ≈250 nM. Furthermore, WC/GCE shows much lower impedance and higher heterogeneous electron transfer rate than bare GCE, indicating the immobilization of WC that accelerates ionic conductivity of the GCE. Owing to its higher electron transfer rate and excellent ionic conductivity, WC/GCE exhibits a tremendous electrochemical sensing performance for the detection of DA. Under optimized conditions, the working range and limit of detection of DA at WC/GCE were estimated to be 0.05 to 700 μM and 14 nM, respectively. The proposed WC/GCE showed good selectivity, stability and reproducibility, and satisfactory recoveries were found in real sample analysis.