MOF-derived NiCo hydroxide for highly efficient non-enzymatic glucose biosensing.

An efficient and robust electrocatalyst is significant for glucose biosensing. The emergence of metal-organic framework (MOF) derived materials opens up new avenues for the development of high-performance glucose sensing catalysts. Herein, MOF derived nickel-cobalt hydroxide supported on conductive copper sheet (NiCo-OH/Cu sheet) is prepared at room temperature. The as-obtained NiCo-OH is endowed with three-dimensional network structure which enables the effective exposure of active materials, sufficient contact between glucose molecule and catalyst. The NiCo-OH/Cu sheet is revealed as good glucose electrochemical sensing material with a wide linear range of 0.05∼6.0 mM and a high sensitivity of 1340µA mM-1cm-2. Additionally, the as-fabricated NiCo-OH/Cu sheet displays good anti-interference ability and long-term stability.

Conformal sulfidation of HKUST-1 for constructing porous Cu2S/CuO octahedrons realizing highly sensitive non-enzymatic glucose detection.

Metal-organic frameworks (MOFs) are believed to be promising precursors for constructing novel and efficient catalysts for glucose sensing. Herein, HKUST-1 precursors are first fabricated using a one-pot hydrothermal approach, and then HKUST-1 is converted into porous Cu2S/CuO octahedrons through conformal sulfidation with the help of OH-ions. The as-obtained Cu2S/CuO composite can provide rich electrochemical active sites and promoted electric transfer kinetics. Benefiting from these combined merits, the as-fabricated Cu2S/CuO composite is confirmed to be a high-performance catalyst, with high sensitivities of 8269.45 and 4140.82µA mM-1cm-2in the corresponding ranges of 0.05 ∼ 0.6 mM and 0.6 ∼ 1.2 mM, respectively. Moreover, the as-prepared electrode materials possess good anti-interference ability, reproducibility and long-term stability. This work opens up new avenues for the design and preparation of transition metal sulfide composites.

Ratiometric fluorescence detection of dopamine based on copper nanoclusters and carbon dots.

Nanoclusters for fluorescence detection are generally comprised of rare and expensive noble metals, and the nanoclusters based on more affordable transition metal have attracted increasing attention. This study designed a ratiometric fluorescent probe to detect dopamine (DA), an important neurotransmitter. With carbon dots encapsulated within silica (CDs@SiO2) as the reference, the emitted reference signal was almost unchanged due to the protection of inert silicon shell. Meanwhile, copper nanoclusters modified with 3-aminophenyl boronic acid (APBA-GSH-CuNCs) provided the sensing signal, in which the phenylboric acid could specifically recognize the cis-diol structure of DA, and caused the fluorescence quenching by photoinduced electron transfer. This dual emission ratiometric fluorescent probe exhibited high sensitivity and anti-interference, and was able to selectively responded to DA with a linear range of 0-1.4 mM, the detection limit of 5.6 nM, and the sensitivity of 815 mM-1. Furthermore, the probe successfully detected DA in human serum samples, yielding recoveries ranging from 92.5% to 102.7%. Overall, this study highlights the promising potential of this ratiometric probe for detecting DA.

Quasi-aligned Cu2S/Cu(OH)2nanorod arrays anchored on Cu foam as self-supported electrode for non-enzymatic glucose detection.

Self-supported Cu2S/Cu(OH)2composite nanorods for highly sensitive non-enzymatic glucose sensing werein situgrown on Cu foam by simple hydrothermal treatment of aligned Cu(OH)2nanorods. The physicochemical and electrochemical properties of the as-fabricated Cu2S/Cu(OH)2composite nanorods were characterized by scanning electron microscopy, transmission electron microscopy, x-ray diffraction, Raman spectroscope, x-ray photoelectron spectroscope, cyclic voltammetry, electrochemical impedance spectroscopy, amperometrici-tmeasurements. The mechanism of the composite nanorods produced on conductive substrates was also explored. The electrode exhibits a sensitivity of 9626.88µA mM-1cm-2towards glucose with good anti-interference ability, indicating it a promising electrode material for the enhanced non-enzymatic glucose detection.

Facile synthesis of Cu/Co-ZIF nanoarrays for non-enzymatic glucose detection.

Cu/Co-ZIF nanoflake arrays on carbon cloth are fabricated by controlling the introducing of Cu2+ions during the growth of Co-ZIF. The Cu/Co-ZIF-20 electrode prepared with 20 mM Cu2+possesses large electrochemically active surface area and bimetallic active sites, which can be revealed by cyclic voltammetry tests. The amperometrici-tmeasurements demonstrate that the Cu/Co-ZIF-20 electrode displays a wide linear range from 0.05 mM to 6.0 mM, and a high sensitivity of 1.03 mA mM-1cm-2. Good selectivity, repeatability and practical applicability indicate its promising application in enzyme-free glucose sensing.

Hierarchically porous CuO spindle-like nanosheets grown on a carbon cloth for sensitive non-enzymatic glucose sensoring.

Herein, porous CuO spindle-like nanosheets were fabricated on a carbon cloth using a facile hydrothermal method, and surface morphology, microstructure, and glucose sensing performance were studied. The porous spindle-like nanosheets are constructed by nanoparticles and slit-like pores, exhibiting a hierarchical structure. When used for non-enzymatic glucose sensoring, the obtained CuO nanosheet electrode exhibits a wide linear range from 0.05 to 3.30 mM, a high sensitivity of 785.2 µA mM-1 cm-2 and a low detection limit of 0.22 µM (S/N = 3). Besides, good selectivity, stability, and reproducibility for glucose detection indicate a promising application of CuO nanosheet electrodes as non-enzymatic glucose sensors.

Co(OH)2 nanosheets decorated Cu(OH)2 nanorods for highly sensitive nonenzymatic detection of glucose.

Co(OH)2 nanosheets/Cu(OH)2 nanorods composite electrodes for non-enzymatic glucose detection were fabricated by electrodepositing Co(OH)2 nanosheets on Cu(OH)2 nanorods substrate grown directly on the copper sheet via a simple one-step reaction. The Co(OH)2 nanosheets/Cu(OH)2 nanorods composite electrode was characterized by scanning electron microscopy, energy dispersive x-ray spectroscopy, x-ray diffraction and x-ray photoelectron spectroscopy. The glucose sensing performance of the composite electrode was investigated by cyclic voltammetry and chronoamperometry. The composite electrode shows high sensitivity of 2366 µA mM-1 cm-2 up to 2 mM with a lower detection limit of 0.17 mM (S/N = 3). The composite electrode is highly selective to glucose in the presence of various substances that always co-exist with glucose in real blood samples. The response of the composite towards human blood serum was in good agreement with that of commercially available glucose sensors, suggesting that a promising electrode material for highly sensitive and selective non enzymatic detection of glucose can be envisioned.

Facile synthesis of a Bi2MoO6/TiO2 nanotube arrays composite by the solvothermal method and its application for high-performance supercapacitor.

In this study, bismuth molybdate/titania nanotube arrays (Bi2MoO6/TNTs) as a binder-free electrode for supercapacitors were fabricated via a facile solvothermal method. The effects of precursor amounts, solvothermal time and temperature on the microstructure and electrochemical properties of the composite were analyzed. The surface morphology, microstructure, chemical composition and chemical states of the composite electrode material were analyzed using scanning electron microscopy, X-ray diffraction, energy dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. Cyclic voltammetry tests, galvanostatic charge-discharge measurements, and electrochemical impedance spectroscopy were employed to analyze the electrochemical behavior of the composite. A specific capacitance of ∼330 mF cm-2 has been achieved for this Bi2MoO6 nanosheets/TNTs composite electrode at the current density of 1 mA cm-2. Galvanostatic charge-discharge experiments suggest a moderate cycling stability together with 76.7% capacitance retention after 1000 cycles of continuous charge-discharge operation. These results indicate that the Bi2MoO6/TNTs composite is a promising electrode material for supercapacitors.

MoO3-x -deposited TiO2 nanotubes for stable and high-capacitance supercapacitor electrodes.

Here we report the supercapacitive properties of a novel MoO3-x /TiO2 nanotube composite prepared by a facile galvanostatic deposition technique and subsequently thermal treatment in an argon atmosphere between 350 °C and 550 °C. X-ray diffraction and X-ray photoelectron spectroscopy confirm the existence of MoO3-x . The MoO3-x /TiO2 electrode prepared at 550 °C exhibits a high specific capacitance of 23.69 mF cm-2 at a scan rate of 10 mV s-1 and good cycling stability with capacitance retention of 86.6% after 1000 cycles in 1 M Na2SO4 aqueous solution. Our study reveals a feasible method for the fabrication of TiO2 nanotubes modified with electroactive MoO3-x as high-performance electrode materials for supercapacitors.