Electro-Oxidation of Glucose in Alkaline Media on Graphene Sheets Decorated with Gold Nanoparticles

In this study the catalytic properties of gold nanoparticles in electro-oxidation process of glucose, were investigated, taking into account, an influence of catalyst composition. Graphene oxide was applied and for electro-oxidation studies of glucose, cyclic voltamperometry was used. It was found that an application of graphene oxide sheets during catalyst synthesis have an influence on gold nanoparticles (AuNPs) size and size distribution. It was confirmed that the application of composite catalyst consisting of graphane-AuNPs significantly changes electro-oxidation of glucose shifting the potential of oxidation to higher positive values and increasing oxidation current.

FeNi Prussian blue analogues on highly graphitized carbon nanosheets as efficient glucose sensors

Meeting the continuous glucose monitoring requirements of individuals necessitates the research and development of sensors with high sensitivity and stability.In this study,a straightforward strategy was proposed for synthesizing ultra-thin oxygen-rich graphitized carbon nanosheets(denoted as GCS-O).These nanosheets are obtained by calcining a topologically two-dimensional indium-based coordination polymer.Subsequently,the growth of FeNi Prussian blue analogue(PBA)on GCS-O effectively introduces active sites and increases the nitrogen content within the carbonaceous matrix.The resulting FeNi-PBA/GCS-O composite exhibits excellent glucose sensing performance with a broad linear range of 1 to 1300μmol·L^(-1).Meanwhile,it also achieves a high sensitivity of 2496μA·mmol^(-1)·L·cm^(-2),a limit of detection of 100nmol·L^(-1)(S/N=3),and commendable long-term durability.The relatively simple synthesis process,exceptional sensitivity,and satisfactory electrochemical sensing performance of FeNi-PBA/GCS-O open up new directions for biosensor applications.

Accelerated reconstruction of ZIF-67 with significantly enhanced glucose detection sensitivity

Research on metal-organic framework(MOF)-based non-enzymatic glucose sensors usually ignores the impact of the surface reconstruction degree of MOF on the activity of catalyzing glucose oxidation.In this work,we choose zeolitic imidazolate framework-67(ZIF-67),which is commonly used in glucose sensing,as a representative to investigate the influence of reconstruction degree on its structure and glucose catalytic performance.By employing the electrochemical activation strategy,the activity of ZIF-67 in catalyzing glucose gradually increased with the prolongation of the activation time,reaching the optimum after 2 h activation.The detection sensitivity of the activated ZIF-67 was 19 times higher than that of the initial ZIF-67,and the limit of detection(LOD)was lowered from 7 to 0.4μM.Our findings demonstrate that the oxidation degree of ZIF-67 deepened rapidly with continuously activation and was basically reconstructed to CoOOH after 2 h activation,accompanied by a morphological change from cuboctahedral to flower-like.Simultaneously,theoretical investigation revealed that ZIF-67 is not suitable as a stable glucose sensor electrode since the adsorbed glucose molecules hasten the dissociation of ligands and the breaking of Co-N bond in ZIF-67.Therefore,our work has important implications for the rational design of next-generation MOF-based glucose sensors.

Catalytic synthesis of diethyl carbonate with supported Pd-Cu bimetallic nanoparticle catalysts:Cu(Ⅰ) as the active species

Cupric oxide （CuO） and copper-cuprous oxide （Cu-Cu2O） nanoparticles were prepared by a simple hydrothermal method for the synthesis of diethyi carbonate （DEC） from ethanol. During these syntheses, varying NaOH and glucose concentrations were applied to explore and pinpoint the active species. It was found that PdCl2/CuO and PdCI2/Cu-Cu2O both catalysts exhibited good thermal stability and morphology. The results of catalytic tests showed that the catalysts prepared with 5 mol/L NaOH show superior catalytic performances because of their lower extent of agglomeration. It is noteworthy that the PdC12/Cu-Cu2O catalysts were the most active, especially the PdCl2/Cu-Cu2O catalyst prepared with 10 mmol glucose and having a higher Cu2O concentration. In Pd（ll）-Cu（II） （PdCl2/CuO） catalysts, there is an induction period, during which Pd（II） is reduced to Pd（0）, that must occur prior to electron transfer between Pd and Cu, and this can slow the catalytic reaction. To further pinpoint the active species, PdCl2/Cu-Cu2O catalysts with different Cu2O contents were prepared by controlling the dosages of glucose. The maximum DEC yield obtained with these catalysts was 151.9 mg.g-1.h-1, corresponding to an ethanol conversion of 7.2% and 97.9% DEC selectivity on an ethanol basis. Therefore, it was concluded that Cu＋ was the active species in this catalytic system, possibly because a higher proportion of Cu＋ reduces the Pd2＋ concentration and limits the CO oxidation side reaction, thus increasing DEC selectivity. In addition, Cu＋ promotes electron transfer between Pd and Cu without an induction period, which could also promote the catalytic activity.

Improved thromboresistance and analytical performance of intravascular amperometric glucose sensors using optimized nitric oxide release coatings

In this work, nitric oxide （NO） release coatings designed for intravenous amperometric glucose sensors are optimized through the use ofa polylactic acid （PLA） layer doped with a lipophilic diazeniumdiolated species that releases NO through a proton-driven mechanism. An Elast-Eon E2As polyurethane coating is used to both moderate NO release from the sensor surface and increase the sensor＇s linear detection range toward glucose. These sensors were evaluated for thromboresistance and in vivo glucose performance through implantation in rabbit veins. By maintaining NO flux on a similar scale to endogenous endothelial cells, implanted glucose sensors exhibited reduced surface clot formation which enables more accurate quantitative glucose measurements continuously. An in vivo time trace of implanted venous sensors demonstrated glucose values that correlated well with the discrete measurements of blood samples on a benchtop point-of-care sensor-based instrument. The raw measured currents from the implanted glucose sensors over 7 h time periods were converted to glucose concentration through use of both a one-point in vivo calibration and a calibration curve obtained in vitro within a bovine serum solution. Control sensors, assembled without NO release functionality, exhibit distinctive surface clotting over the 7 h in vivo implantation period.

Ni_(4)-thiacalix[4]arene sandwiched Mo_8 polyoxometalate bimetallic nanoclusters for electrocatalytic glucose oxidation

Available online two new Ni_(8)Mo_(8) bimetallic coordination clusters,[Ni_(4)(TC4A)]_(2)[(Mo_5~VMo_(3)~ⅥO_(24))(PO_(4))](+Solvent)(Ni_(8)PMo_(8),H_(4)TC4A=p-tert-butylthiacalix[4]arene) and[Ni_(4)(TC4A)]_(2)[(Mo_5~VMo_(3)~ⅥO_(24))(OH)(CO_(3))](+Solvent)(Ni_(8)Mo_(8)),were synthesized by solvothermal method and structurally characterized by single-crystal X-ray diffraction,powder X-ray diffraction,FT-IR spectroscopy,and TGA experiments,respectively.The usage of H_(3)PMo_(12)O_(40) as source for Ni_(8)PMo_(8) resulted a sandwich like structure built from two Ni_(4)-thiacalix[4]arene units and a Mo_(8) polyoxometalate with inner spaces of PO_(4)^(3-).Ni_(8)Mo_(8) with the similar structure to that of Ni_(8)PMo_(8) is from H_(2)MoO_(4) starting reagent with OH^(-)and CO_(3)^(2-)anions encapsulated in the center.The two clusters can be directly loaded on carbon paper and utilized as working electrodes which showed distinguishable performances for glucose detection and oxidation.This work provides a better understanding of the structure-property relationships in using substituted polyoxometalates for electrochemical applications and is helpful for building calixarene-based or polyoxometalatebased functional materials.

Correlation between blood glucose fluctuations and activation of oxidative stress in type 1 diabetic children during the acute metabolic disturbance period

Background Studies have shown that complications in type 1 diabetes mellitus （T1DM） in children are mainly due to oxidative stress （OS）. Lipid peroxidation is the main marker of OS and iso-prostaglandin is a reliable biomarker of lipid peroxidation in type 2 diabetes mellitus （T2DM）. However, there have been few studies on OS in T1DM children with hyperglycemia and glucose fluctuations.

Biosynthesized Gold/Activated Carbon Catalyst for Aerobic Glucose Oxidation： Influence of Acid Treatment on Activated Carbon

The biosynthesized gold/activated carbon catalysts for glucose oxidation were prepared with Cacumen platycladi leaves extract,and activated carbon （AC） was modified with hydrochloric acid and nitric acid to modify its surface chemistry and used as supports.The catalysts with acid-treated AC exhibited improving activity for the selective oxidation of glucose,when compared to that with untreated one.In order to investigate the influence of the acid treatment for the catalysts performance,the surface chemical properties of AC were characterized by BrunauerEmmett-Teller surface area characterization,Boehm titration,X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy,respectively.The dispersion of AuNPs on AC was observed by transmission electron microscopy and X-ray diffraction.The results indicated that the catalysts with acid treated supports showed improved dispersion than that of untreated one,which may be the result that the supports significantly increase the surface functional groups and remove the ash after acid treatment.

Dopant-stimulated CuO Nanofibers for Electro-oxidation and Determination of Glucose

We described the preparation of copper oxide composite nanofibers doped with carbon nanotubes （CuO/C-NFs） or nickel oxide（CuO/NiO-NFs） by electrospinning for direct glucose determination. The interest in exploring practical CuO/C-NFs and CuO/NiO-NFs electrode materials for sensor application was fascinated by the possibility of promoting electron transfer for kinetically unfavorable glucose oxidation reactions at a lower overpo- tential and thus improving the selectivity of the electrode for glucose in electroanalysis. The morphologies of CuO/C-NFs and CuO/NiO-NFs were characterized by scanning electron microscopy（SEM） and X-ray powder diffraction（XRD）. The electrocatalytic performances of glucose were evaluated in detail by cyclic voltammetry（CV） and chronoamperometry. Facile charge transport, enhanced current response（at a lower overpotential of ＋0.35 V）, improved stability and selectivity, as well as excellent resistance towards electrode fouling were observed at CuO/ C-NFs electrode in direct glucose electroanalysis. These merits are attributed to the highly porous three-dimensional network film structure of CuO/C-NFs electrode materials and the potential synergic catalytic effect of CuO and carbon nanotubes in composite nanofibers. This study may provide a new insight into metal oxide-based composite nanofibers obtained via electrospinning for fabricating novel and high performance sensors and devices.

Effect of reduction method on the performance of Pd catalysts supported on activated carbon for the selective oxidation of glucose

The effect of the reduction method on the catalytic properties of palladium catalysts supported on activated carbon for the oxidation of D-glucose was examined.The reduction methods investigated include argon glow discharge plasma reduction at room temperature,reduction by flowing hydrogen at elevated temperature,and reduction by formaldehyde at room temperature.The plasma-reduced catalyst shows the smallest metal particles with a narrow size distribution that leads to a much higher activity.The catalyst characteristics show that the plasma reduction increases the amount of oxygen-containing functional groups,which significantly enhances the hydrophilic property of the activated carbon and improves the dispersion of the metal.

Ru-Co-Mn trimetallic alloy nanocatalyst driving bifunctional redox electrocatalysis

Water electrolysis is one of the most promising approaches for producing hydrogen.However,it has been hindered by the sluggishness of the anodic oxygen evolution reaction.In this work,we fabricated Ru-Co-Mn trimetallic alloy nanoparticles on N-doped carbon support(RuCoMn@NC)via the pyrolysis-adsorption-pyrolysis process using ZIF-67 as a precursor.The RuCoMn@NC catalyst exhibited excellent electrocatalytic performance for the hydrogen evolution reaction(HER)over a wide range of pH and glucose oxidation reaction in alkaline media.It showed exceptional HER activity in alkaline medium,superior to that of the commercial Pt/C catalyst(20 wt%),and good electrochemical stability.Further,a two-electrode alkaline electrolyzer pairing RuCoMn@NC as both cathode and anode was employed,and only a cell voltage of 1.63 V was required to attain a current density of 10 mA cm^(-2)in glucose electrolysis,which is about 270 mV lower than that in the overall water-splitting electrolyzer.This paper provides a promising method for developing efficiently bifunctional electrocatalysts driving redox electrocatalysis,and it would be beneficial to energy-saving electrolytic H_(2) production.