Synthesizing NiAl-layered double hydroxide microspheres with hierarchical structure and electrochemical detection of hydroquinone and catechol

Anab initiostudy of catechol sensing in pristine and transition metal decoratedγ-graphyne

Catechol is a toxic biomolecule due to its low degradability to the ecosystem and unpredictable impact on human health. In this work, we have investigated the catechol sensing properties of pristine and transition metal (Ag, Au, Pd, and Ti) decoratedγ-graphyne (GY) systems by employing the density functional theory and first-principles molecular dynamics approach. Simulation results revealed that Pd and Ti atom is more suitable than Ag and Au atom for the decoration of the GY structure with a large charge transfer of 0.29e and 1.54e from valence d-orbitals of the Pd/Ti atom to the carbon-2p orbitals of GY. The GY + Ti system offers excellent electrochemical sensing towards catechol with charge donation of 0.14e from catechol O-p orbitals to Ti-d orbitals, while the catechol molecule is physisorbed to pristine GY with only 0.04e of charge transfer. There exists an energy barrier of 5.19 eV for the diffusion of the Ti atom, which prevents the system from metal-metal clustering. To verify the thermal stability of the sensing material, we have conducted the molecular dynamics simulations at 300 K. We have reported feasible recovery times of 2.05 × 10^-5s and 4.7 × 10²s for sensing substrate GY + Pd and GY + Ti, respectively, at 500 K of UV light.

Using photo-induced p-n junction interface effect of CoMn2O4/β-MnO2 oxidase mimetics for colorimetric determination of hydroquinone in seawater

Detection of pollutants in seawater faces a great challenge of strong interference, and the facile detection method is lacked. The CoMn₂O₄/β-MnO₂ p-n junction oxidase mimetics were successfully prepared for colorimetric detection of hydroquinone in seawater. The catalysis ability was enhanced significantly by the photo-induced p-n junction interface effect. It not only promoted the formation of H₂O₂ by suppressing the recombination of photon-generated carriers, but also provided the driving force for electron transport. The colorimetric detection of hydroquinone was achieved by fading and exhibited good adaptability in seawater. The obtained good recovery rate (97.23%-101.37%) in seawater makes it an inspiring method for practical application. The photo-induced p-n junction interface effect provides an opportunity for developing the application of colorimetric sensing in seawater detection.

Graphene oxide–porphyrin composite nanostructure included electrochemical sensor for catechol detection

A novel composite nanostructure (GO–Por) has been prepared via ultrasonication and exhibited enhanced electrocatalytic activity towards catechol oxidation.

A study on the electrochemical behavior of hydroquinone at a nanometer cobalt/l-glutamate-modified electrode

A new electrochemical sensor for hydroquinone (HQ) was prepared. The electrochemical sensor was modified by electrodeposition and electrochemical polymerization to modify nanometer cobalt (nano-Co) and poly-l-glutamic acid (poly-l-glu) on the surface of a glassy carbon electrode (GCE). Then, the electrochemical behavior of hydroquinone on the electrochemical sensor was investigated by cyclic voltammetry (CV). The experimental conditions were optimized from the aspects of electrolyte type, concentration, acidity, enrichment time and scanning speed. The experimental results showed that under optimized conditions the oxidation peak current has a good linear relationship with the concentration of hydroquinone in the range of 3.85 × 10⁻⁶ to 1.30 × 10⁻³ mol L⁻¹ (R² = 0.9998). Moreover, there was a low detection limit of 4.97 × 10⁻⁷ mol L⁻¹. When the sensor was used for the analysis of hydroquinone in water samples, the recoveries with satisfactory results were in the range of 97.2–102.6%.

A new electrochemical sensor for hydroquinone (HQ) was prepared.

Continuous and Rapid Synthesis of UiO-67 by Electrochemical Methods for the Electrochemical Detection of Hydroquinone

Continuous and rapid synthesis of UiO-67 under mild conditions has been achieved by electrochemical methods for the first time. In the reaction system, a zirconium sheet was utilized as electrodes and a metal source for the assembly of UiO-67. High-crystalline UiO-67 with a regular tetrahedral morphology of around 1 μm was obtained within 1.5 h under the optimized solvent composition, voltage, and temperature conditions. This electrochemical synthetic method of UiO-67 in our work overcomes the shortcomings of high temperature and pressure of a traditional solvothermal method, which proposes new ideas for the large-scale and rapid synthesis of UiO-67. The UiO-67 synthesized by an electrochemical method was prepared as a UiO-67-carbon paste electrode (CPE), which exhibited a linear response to hydroquinone (HQ) in the range of 5-300 μM with a detection limit of 3.6 × 10^-9 M (S/N = 3), for the electrochemical detection of HQ. It was confirmed that UiO-67-CPE possessed excellent reusability and antiinterference ability for the detection of HQ, and its detection ability even did not change after standing for 3 months. We further tried to apply UiO-67-CPE to the practical determination of HQ in tap water and river water samples, and the results proved that the recovery rate is 97.9-104.7% in real samples.

A glassy carbon electrode modified with cerium phosphate nanotubes for the simultaneous determination of hydroquinone, catechol and resorcinol

A nafion film containing cerium phosphate nanotubes was pasted onto a glassy carbon electrode (GCE) to obtain a sensor for hydroquinone (HQ). The morphologies and components of the coating were characterized by transmission electron microscopy, scanning electron microscopy and energy-dispersive spectroscopy. Cyclic voltammetry and differential pulse voltammetry (DPV) showed the specific surface of the electrode to be significantly increased and the electron transfer rate to be accelerated. The modified GCE was applied to the determination of hydroquinone (HQ) via DPV. The oxidation current increases linearly in the 0.23 μM to 16 mM HQ concentration range which is as wide as five orders of magnitude. The limit of detection is 0.12 μM (based on a signal-to-noise ratio of 3), and the sensitivity is 1.41 μA·μM^-1 cm^-2. The method was further applied to the simultaneous determination of HQ, catechol and resorcinol. The potentials for the three species are well separated (20, 134, and 572 mV vs SCE). Average recoveries from (spiked) real water samples are between 95.2 and 107.0%, with relative standard deviations of 0.9~2.7% (for n = 3) at three spiking levels. The method was validated by independent assays using HPLC. Graphical abstract ᅟ.