Synthesis, characterization, and electrochemical performances of core-shell Ni(SO4)0.3(OH)1.4/C and NiO/C nanobelts

Abstract

In this study, Ni(SO₄)_0.3(OH)_1.4 nanobelts have been synthesized via a simple template-free hydrothermal reaction in an aqueous solution containing nickel sulfate and sodium acetate. It is found that the molar ratio of nickel sulfate to sodium acetate plays a very important role in determining the morphology of the final product. Subsequently, core-shell Ni(SO₄)_0.3(OH)_1.4/C composite nanobelts have been synthesized from the carbonization and polymerization of glucose under mild hydrothermal conditions in the presence of newly produced Ni(SO₄)_0.3(OH)_1.4 nanobelts. The shell thickness of the core-shell nanobelts can be varied from 2 to 18 nm by adjusting the concentration of glucose. Additionally, the structural evolution from core-shell Ni(SO₄)_0.3(OH)_1.4/C to NiO/C has been successfully performed through ex situ heat treatment. The belt-like morphology has still been maintained after heat treatment at 600 °C for 2 h. The as-prepared NiO/C composites were directly immobilized onto the surface of glassy carbon electrode (GCE) for nonenzymatic glucose determination. The fabricated glucose sensor has an ultrasensitive response (149.11 μA mM⁻¹) and a low detection limit of 9.12 nM (signal/noise ratio (S/N) = 3), which are among the best values reported in the literature.