Electrochemical preparation of a composite gold–cobalt electrode and its electrocatalytic activity in alkaline medium

Ultrafast one-pot anodic preparation of Co3O4/nanoporous gold composite electrode as an efficient nonenzymatic amperometric sensor for glucose and hydrogen peroxide

For fabrication of composite electrode, one-pot strategy is highly attractive for convenience and efficiency. Here, a self-supporting Co₃O₄/nanoporous gold (NPG) composite electrode was one-pot prepared via one-step in situ anodization of a smooth gold electrode in a CoCl₂ solution within 100 s. It worked as a bifunctional electrocatalyst for glucose oxidation and H₂O₂ reduction in NaOH solution. Under optimized conditions, the electrocatalytic oxidation of glucose exhibits a wide linear range from 2 μM to 2.11 mM with a limit of detection as low as 0.085 μM (S/N = 3) and an ultrahigh sensitivity of 4470.4 μA mM^-1 cm^-2. Detection of glucose in human serum samples are also realized with results comparable to those from local hospital. The electrocatalytic reduction of H₂O₂ shows a linear response range from 20 μM to 19.1 mM and a high sensitivity of 1338.7 μA mM^-1 cm^-2. The present results demonstrate that the facilely prepared Co₃O₄/NPG is a promising nonenzymatic sensor for rapid amperometric detection of glucose and H₂O₂ with ultrasensitivity, high selectivity, satisfactory reproducibility, good stability and long duration.

Recent advances in electrochemical non-enzymatic glucose sensors - A review

This review encompasses the mechanisms of electrochemical glucose detection and recent advances in non-enzymatic glucose sensors based on a variety of materials ranging from platinum, gold, metal alloys/adatom, non-precious transition metal/metal oxides to glucose-specific organic materials. It shows that the discovery of new materials based on unique nanostructures have not only provided the detailed insight into non-enzymatic glucose oxidation, but also demonstrated the possibility of direct detection in whole blood or interstitial fluids. We critically evaluate various aspects of non-enzymatic electrochemical glucose sensors in terms of significance as well as performance. Beyond laboratory tests, the prospect of commercialization of non-enzymatic glucose sensors is discussed.

Electrodeposition of a 3D hierarchical porous flower-like cobalt–MWCNT nanocomposite electrode for non-enzymatic glucose sensing

A versatile and cost-effective electrodeposition technique was adopted to synthesize cobalt and cobalt–MWCNT nanocomposite electrodes and the fabricated cobalt–MWCNT material was successfully demonstrated as a non-enzymatic glucose sensor.

Highly sensitive determination of reduced glutathione based on a cobalt nanoparticle implanted-modified indium tin oxide electrode

Cobalt nanoparticle modified indium tin oxide (CoNP/ITO) electrodes fabricated by ion implantation were applied for the detection of reduced glutathione (GSH).

Water on Au sputtered films

Transient changes in the contact angle, Δθ ∼ 10°, of water on gold (Au) reveal reversible wetting of near hydrophobic Au films.

Characterisation of Nanostructured Co3O4 Synthesised by the Thermal Decomposition of an Inorganic Precursor

Nanocrystalline Co3O4 has been synthesised using an inorganic precursor via thermal decomposition. The prepared inorganic precursor Co(cinnamate)2(N2H4)2 was characterised by hydrazine and metal analyses, infrared spectral analysis, and thermogravimetric analysis. Using appropriate annealing conditions, cobalt oxide nanoparticles of average size ~11 nm were synthesised by thermal treatment of the precursor. The nanoparticles’ size and structure were characterised using X-ray diffraction, high-resolution transmission electron microscopy, selected-area electron diffraction, and scanning electron microscopy techniques.

Preparation and Characterization of Copper-Doped Cobalt Oxide Electrodes

Cobalt oxide (Co3O4) and copper-doped cobalt oxide (CuxCo(3-x)O4) films have been prepared onto titanium support by the thermal decomposition method. The electrodes have been characterized by different techniques such as cyclic voltammetry, scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy (XPS). The effect on the electrochemical and crystallographic properties and surface morphology of the amount of copper in the oxide layer has been analyzed. The XPS spectra correspond to a characteristic monophasic Cu-Co spinel oxides when x is below 1. However, when the copper content exceeds that for the stoichiometric CuCo2O4 spinel, a new CuO phase segregates at the surface. The analysis of the surface cation distribution indicates that Cu(II) has preference for octahedral sites.