Preparation and comparison of colloid based Ni50Co50(OH)2/BOX electrocatalyst for catalysis and high performance nonenzymatic glucose sensor

Electrochemical fabrication of Co(OH)2 nanoparticles decorated carbon cloth for non-enzymatic glucose and uric acid detection

Cobalt hydroxide nanoparticles (Co(OH)₂ NPs) were uniformly deposited on flexible carbon cloth substrate (Co(OH)₂@CC) rapidly by a facile one-step electrodeposition, which can act as an enzyme-free glucose and uric acid sensor in an alkaline electrolyte. Compositional and morphological characterization were examined by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS), which confirmed the deposited nanospheres were Co(OH)₂ nanoparticles (NPs). The electrochemical oxidation of glucose and uric acid at Co(OH)₂@CC electrode was investigated by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), differential pulse voltammetry (DPV), and chronoamperometry methods. The results revealed a remarkable electrocatalytic activity toward the single and simultaneous determination of glucose and uric acid at about 0.6 V and 0.3 V (vs. Ag/AgCl), respectively, which is attributed to a noticeable synergy effect between Co(OH)₂ NPs and CC with good repeatability, satisfactory reproducibility, considerable long-term stability, superior selectivity, outstanding sensitivity, and wide linear detection range from 1 uM to 2 mM and 25 nM to 1.5 uM for glucose and UA, respectively. The detection limits were 0.36 nM for UA and 0.24 μM for glucose (S/N = 3). Finally, the Co(OH)₂@CC electrode was utilized for glucose and uric acid determination in human blood samples and satisfying results were obtained. The relative standard derivations (RSDs) for glucose and UA were in the range 6 to 14% and 0 to 3%, respectively. The recovery ranges for glucose an UA were 97 to 103% and 95 and 101%, respectively. These features make the novel Co(OH)₂@CC sensor developed by a low-cost, efficient, and eco-friendly preparation method a potentially practical candidate for application to biosensors.

Novel Synthesis of Sensitive Cu-ZnO Nanorod-Based Sensor for Hydrogen Peroxide Sensing

We aimed to synthesize sensitive electrochemical sensors for hydrogen peroxide sensing by using zinc oxide nanorods grown on a fluorine-doped tin oxide electrode by using the facial hydrothermal method. It was essential to keep the surface morphology of the material (nanorods structure); due to its large surface area, the concerned material has enhanced detection ability toward the analyte. The work presents a non-enzymatic H₂O₂ sensor using vertically grown zinc oxide nanorods on the electrode (FTO) surfaces with Cu nanoparticles deposited on zinc oxide nanorods to enhance the activity. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-Ray (EDX), X-ray diffraction (XRD), and electrochemical methods were used to characterize copper–zinc oxide nanorods. In addition to the high surface area, the hexagonal Cu-ZnO nanorods exhibited enhanced electrochemical features of H₂O₂ oxidation. Nanorods made from Cu-ZnO exhibit highly efficient sensitivity of 3415 μAmM⁻¹cm⁻² low detection limits (LODs) of 0.16 μM and extremely wide linear ranges (0.001–11 mM). In addition, copper-zinc oxide nanorods demonstrated decent reproducibility, repeatability, stability, and selectivity after being used for H₂O₂ sensing in water samples with an RSD value of 3.83%. Cu nanoparticles decorated on ZnO nanorods demonstrate excellent potential for the detection of hydrogen peroxide, providing a new way to prepare hydrogen peroxide detecting devices.

A Non-enzymatic Hydrogen Peroxide Sensor with Enhanced Sensitivity Based on Pt Nanoparticles

The non-enzymatic electrochemical sensing platform for hydrogen peroxide by using Pt-based nanoparticle was investigated. The characterization of PtNiCo-NPs was done by XRD, TEM, HRTEM, EDS, and XPS. A simple drop-casting technique was used to fabricate the nanomaterial on FTO electrode. The amperometric and cyclic voltammetric results illustrated that PtNiCo-NPs on FTO had excellent electrochemical performance over other mono or bimetallic materials. The catalytic performance for H₂O₂ sensing based on PtNiCo-NPs possessed a wide linear range from 5 μM to 16.5 mM with a low detection limit of 0.37 μM and a good sensitivity of 1374.4 μA mM^-1 cm^-2 at a scan rate of 20 mV s^-1 (vs. Ag/AgCl). This work presents a new way to produce a ternary nanomaterial for H₂O₂ sensing with excellent electrochemical performance. In addition, the fabricated nanomaterial showed no interferences for common interfering agents, which indicates the high specificity of the sensor. The PtNiCo-NPs have excellent stability and good reproducibility in real samples.