Effects of precursor salt on colloidal cobalt oxyhydroxides composition and its application in non-enzymatic glucose

Abstract

Colloidal cobalt oxyhydroxide [CoO(OH)] has been prepared from precursors cobalt acetate and cobalt nitrate. The cobalt colloids (Co.Acetate and Co.Nitrate) were characterized by simultaneous thermogravimetric/differential thermal analysis, scanning electron microscopy with energy-dispersive X-ray spectroscopy, Fourier transform infrared and electronic spectroscopy. Characterization data indicated the presence of counter ions (CH 3 COOand NO 3-), likely intercalated within the structure of the colloidal cobalt. The platinum working electrode chemically modified with cobalt colloid was studied by cyclic voltammetry in alkaline solution [0.5 M, NaOH], which revealed differences in the reproducibility and stability of the electroactive material. The colloidal Co.Nitrate modified electrode was applied to the non-enzymatic glucose (Glu) electrooxidation in the concentration range from 7.2 to 21.9 × 10-8 mol L-1. The limits of detection (5.87 × 10-8 mol L-1) and quantitation (1.96 × 10-7 mol L-1) calculated suggest that colloidal Co.Nitrate has the potential to be used as a sensor for low glucose concentration.

Unraveling Nanoscale Cobalt Oxide Catalysts for the Oxygen Evolution Reaction: Maximum Performance, Minimum Effort

“…No intense δ(B−OH)/ν(OBO) band at around 1323 cm −1 can be detected for any of the "Standard" samples under catalytic conditions, which shows that the precursor completely changed during catalysis, which correlates well with the decreasing amount of incorporated boron evident from ICP-MS results. 56 For the Standard-L-1min sample, typical Co 3 O 4 signals can be observed in the fingerprint region. The two signals at 557 and 656 cm −1 can be correlated with the stretching vibration modes of ν(Co 3+ octahedral O) and ν(Co 2+ tetrahedral O), respectively.…”

Bimetallic Layered Hydroxide Nitrate@Graphene Oxide as an Electrocatalyst for Efficient Non-Enzymatic Glucose Sensors: Tuning Sensitivity by Hydroxide-Regulated M2(OH)4–n(An–) Phases Derived from Solvent Engineering

“…Electrocatalytic glucose oxidation on TMCs often involves the conversion of surface hydroxide (M–OH) to oxyhydroxide (MOOH) in an alkaline medium, which by itself is an excellent electrocatalyst, hence TMCs are known as precatalysts, and is also common in electrochemical water splitting . For instance, cobalt oxyhydroxide (CoOOH) is known to exhibit excellent electrocatalytic activity, reversible electrochemical behavior, and high stability under alkaline conditions and its morphology can be facilely controlled on the nanoscale …”