Hierarchical tungsten-doped bimetallic selenides nanosheets arrays/nickel foam composite electrode as efficient gallic acid electrochemical sensor.

The development of effective and accurate gallic acid (GA) electrochemical sensors is critical for food and pharmaceutical industry and health perspectives. Multi-step hydrothermal treatments of bimetallic (Ni/Co) flaky bimetallic hydroxides (NiCo FBHs) were employed to prepare tungsten-doped cobalt-nickel selenides nanosheets arrays (W-Co 0.5 Ni 0.5 Se 2 NSAs) serving  as the main active substance of GA detection. The morphology and composition of the W-Co 0.5 Ni 0.5 Se 2 NSAs/NF were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, X-ray powder diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The GA electrochemical sensor constructed by the W-Co 0.5 Ni 0.5 Se 2 NSAs/NF composite electrode exhibits two linear concentration ranges of 1.00-36.2 μM and 36.2-1.00×10 3 μM for GA electrochemical detection with a limit of detection of  0.120 μM (S/N=3) at the working potential of 0.05 V (vs. SCE). The W-Co 0.5 Ni 0.5 Se 2 NSAs/NF shows high selectivity, good long-term stability, high recovery in the range 97.9-105%, and a relative standard deviation (RSD) between 0.60 and 2.7%.