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_0.5Ni_0.5Se₂ NSAs) serving  as the main active substance of GA detection. The morphology and composition of the W-Co_0.5Ni_0.5Se₂ 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_0.5Ni_0.5Se₂ NSAs/NF composite electrode exhibits two linear concentration ranges of 1.00-36.2 μM and 36.2-1.00×10³ 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_0.5Ni_0.5Se₂ 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%.