Highly sensitive dopamine electrochemical sensing method based on hollow dodecahedron zinc-cobalt bimetallic sulfide

Bimetallic sulfides have attracted extensive attention due to their abundant active sites, high electrochemical activity and low cost. Here, hollow zinc-cobalt bimetallic sulfides (H-Zn_xCo_3−xS₄) with different Zn/Co molar ratios and hollow metal-cobalt bimetallic sulfides (H-M_0.30Co_2.70S₄) with different second metal doping (M = Zn, Cu, Ni) were synthesized by facile co-precipitation and solvothermal sulfidation methods. And then, a novel electrochemical sensing method for the detection of dopamine (DA) was established based on hollow bimetallic sulfide materials. The morphologies, compositions and structures of these compounds were characterized by Scanning electron microscopic, Transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and N₂ adsorption/desorption isotherm. These characterization results indicated that bimetallic sulfides with hollow rhombic dodecahedron structured were successfully prepared, and the diameter of the cavity inside and the thickness of the outer shell were close to 550 and 50 nm, respectively. Moreover, electrochemical results demonstrated that DA sensor based on H-Zn_0.30Co_2.70S₄ materials had the highest current response compared to other as-prepared co-based metal sulfides. The linear range of H-Zn_0.30Co_2.70S₄/glassy carbon electrode (GCE) sensor was 0.01–77.0 and 77.0–277.0 μM, the sensitivity was 458.1 and 254.9 μA mM⁻¹ cm⁻², respectively, and the detection limit was determined to be 3 nM (S/N＝3). Compared with similar type DA sensors, the linear range of this sensor was expanded by an order of magnitude, and the detection limit was reduced by an order of magnitude. Additionally, the DA sensor displayed good selectivity, satisfactory reproducibility and stability. Rational design of well-controlled hollow bimetallic sulfides materials would bring new perspectives to the construction of high-performance electrochemical sensors and provide additional options for drug analysis.