Electrocatalytic Oxidation Of Glucose Research Articles

Chemically reduced silver nanoparticles: preparation and applications

By virtue of their unique physiochemical properties, silver nanoparticles (AgNPs) have attracted enormous research interest for versatile applications. It is critical to study the effect of the microstructure – for example, the shape and the size of AgNPs – on their performance. Herein, AgNPs with varying shapes and sizes were synthesized by varying the manner that the reducing agent sodium borohydride (NaBH4) was added (i.e. multistep and one-step reduction methods) and then were studied for photocatalysis of dyes and electrocatalytic oxidation of glucose. The results showed that triangular AgNPs, spherical AgNPs or a mixture of triangular- and spherical-shaped AgNPs was obtained from the multistep reduction method, whereas only spherical-shaped AgNPs were yielded from the one-step reduction method. The sizes could be manipulated by changing the concentrations of the reagents or the reaction temperature. The triangular-shaped and smaller-sized AgNPs were more effective for photocatalysis of dyes, and the degradation percentage of methylene blue was enhanced to 95% for the silver (Ag)–titanium dioxide (TiO2) complex from 50% for pure titanium dioxide. Moreover, the spherical-shaped AgNPs with a smaller size could effectively detect glucose at a very low concentration of 5–10 mM with an excellent glucose tolerance.

Investigation of glucose biosensors by non-enzymatic photoluminescent detection using oleic acid treated Ag2S nanoparticles

The immobilization of carboxylic acid moieties on the surface of nanoparticles to promote the development of non-enzymatic detection of target molecules (sensors) with better feasibility and selectivity has been investigated. This work is focused on treating Ag2S nanoparticles with Oleic acid, a potential carboxylic acid moiety with good stereochemical compatibility, photochemical responses, photoluminescence (PL) quantum yield, and biocompatibility. The hydrothermally synthesized Ag2S was crystalline in nature with a monoclinic crystal system, as inferred from X-ray diffractograms. The surface morphology of Ag2S studied using the SEM micrographs showed nearly spherical and fused particles. ATR-FTIR was recorded by the compensation method in the wavenumber range 600–4000 cm−1 and the changes in the chemical composition of pristine Ag2S and Oleic acid-treated Ag2S (with or without glucose molecules) were investigated. UV–Vis analysis was carried out to establish the absorption region of the respective nanoparticles, and the corresponding inferred excitation wavelength (396 nm) was fixed for the PL analysis. Photoluminescence spectra (PL) of Ag2S with oleic acid and glucose at various concentrations showed a reduction in PL intensity as glucose concentration increased. This PL reduction arises due to various oxidation processes that take place on the large surface of Oleic acid-treated Ag2S. Chronoamperometric studies were used to analyze the electrocatalytic glucose oxidation that occurs in Ag2S nanoparticles with Oleic acid with a low-cost procedure. The concentration of glucose was varied from 0.25 to 30 mM, and the significant sensing abilities of the oleic acid-treated Ag2S were demonstrated.

Boosted Electrocatalytic Glucose Oxidation Reaction on Noble-Metal-Free MoO3-Decorated Carbon Nanotubes

Electrocatalytic glucose oxidation reaction (GOR) has attracted much attention owing to its crucial role in biofuel cell fabrication. Herein, we load MoO3 nanoparticles on carbon nanotubes (CNTs) and use a discharge process to prepare a noble-metal-free MC-60 catalyst containing MoO3, Mo2C, and a Mo2C–MoO3 interface. In the GOR, MC-60 shows activity as high as 745 µA/(mmol/L cm2), considerably higher than those of the Pt/CNT (270 µA/(mmol/L cm2)) and Au/CNT catalysts (110 µA/(mmol/L cm2)). In the GOR, the response minimum on MC-60 is as low as 8 µmol/L, with a steady-state response time of only 3 s. Moreover, MC-60 has superior stability and anti-interference ability to impurities in the GOR. The better performance of MC-60 in the GOR is attributed to the abundant Mo sites bonding to C and O atoms at the MoO3–Mo2C interface. These Mo sites create active sites for promoting glucose adsorption and oxidation, enhancing MC-60 performance in the GOR. Thus, these results help to fabricate more efficient noble-metal-free catalysts for the fabrication of glucose-based biofuel cells.Graphical abstract

ZIF-67 Anchored on MoS2/rGO Heterostructure for Non-Enzymatic and Visible-Light-Sensitive Photoelectrochemical Biosensing.

Graphene and graphene-like two-dimensional layered nanomaterials-based photoelectrochemical (PEC) biosensors have recently grown rapidly in popularity thanks to their advantages of high sensitivity and low background signal, which have attracted tremendous attention in ultrahigh sensitive small molecule detection. This work proposes a non-enzymatic and visible-light-sensitive PEC biosensing platform based on ZIF-67@MoS2/rGO composite which is synthesized through a facile and one-step microwave-assisted hydrothermal method. The combination of MoS2 and rGO could construct van der Waals heterostructures, which not only act as visible-light-active nanomaterials, but facilitate charge carriers transfer between the photoelectrode and glassy carbon electrode (GCE). ZIF-67 anchored on MoS2/rGO heterostructures provides large specific surface areas and a high proportion of catalytic sites, which cooperate with MoS2 nanosheets, realizing rapid and efficient enzyme-free electrocatalytic oxidation of glucose. The ZIF-67@MoS2/rGO-modified GCE can realize the rapid and sensitive detection of glucose at low detection voltage, which exhibits a high sensitivity of 12.62 μAmM-1cm-2. Finally, the ZIF-67@MoS2/rGO PEC biosensor is developed by integrating the ZIF-67@MoS2/rGO with a screen-printed electrode (SPE), which exhibits a high sensitivity of 3.479 μAmM-1cm-2 and a low detection limit of 1.39 μM. The biosensor's selectivity, stability, and repeatability are systematically investigated, and its practicability is evaluated by detecting clinical serum samples.

Complete Glucose Electrooxidation Enabled by Coordinatively Unsaturated Copper Sites in Metal-Organic Frameworks.

The electrocatalytic oxidation of glucose plays a vital role in biomass conversion, renewable energy, and biosensors, but significant challenges remain to achieve high selectivity and high activity simultaneously. In this study, we present a novel approach for achieving complete glucose electrooxidation utilizing Cu-based metal-hydroxide-organic framework (Cu-MHOF) featuring coordinatively unsaturated Cu active sites. In contrast to traditional Cu(OH)2 catalysts, the Cu-MHOF exhibits a remarkable 40-fold increase in electrocatalytic activity for glucose oxidation, enabling exclusive oxidation of glucose into formate and carbonate as the final products. The critical role of open metal sites in enhancing the adsorption affinity of glucose and key intermediates was confirmed by control experiments and density functional theory simulations. Subsequently, a miniaturized nonenzymatic glucose sensor was developed showing superior performance with a high sensitivity of 214.7 μA mM-1 cm-2 , a wide detection range from 0.1 μM to 22 mM, and a low detection limit of 0.086 μM. Our work provides a novel molecule-level strategy for designing catalytically active sites and could inspire the development of novel metal-organic framework for next-generation electrochemical devices.

Complete Glucose Electrooxidation Enabled by Coordinatively Unsaturated Copper Sites in Metal–Organic Frameworks

AbstractThe electrocatalytic oxidation of glucose plays a vital role in biomass conversion, renewable energy, and biosensors, but significant challenges remain to achieve high selectivity and high activity simultaneously. In this study, we present a novel approach for achieving complete glucose electrooxidation utilizing Cu‐based metal‐hydroxide‐organic framework (Cu‐MHOF) featuring coordinatively unsaturated Cu active sites. In contrast to traditional Cu(OH)2 catalysts, the Cu‐MHOF exhibits a remarkable 40‐fold increase in electrocatalytic activity for glucose oxidation, enabling exclusive oxidation of glucose into formate and carbonate as the final products. The critical role of open metal sites in enhancing the adsorption affinity of glucose and key intermediates was confirmed by control experiments and density functional theory simulations. Subsequently, a miniaturized nonenzymatic glucose sensor was developed showing superior performance with a high sensitivity of 214.7 μA mM−1 cm−2, a wide detection range from 0.1 μM to 22 mM, and a low detection limit of 0.086 μM. Our work provides a novel molecule‐level strategy for designing catalytically active sites and could inspire the development of novel metal–organic framework for next‐generation electrochemical devices.

3D Nitrogen-Doped Porous Carbon Supported Pt Catalyst for Electrocatalytic Oxidation of Glucose

Glucose fuel cells have attracted widespread attention in the biomedical field due to their ability to generate electrical energy continuously. The development of this technology has great potential in the application of powering implantable medical devices. However, the efficiency of the glucose oxidation reaction at the anode of the fuel cell is low, and a catalyst needs to be added to improve the reaction efficiency. Platinum (Pt) catalysts are prone to agglomerate during use, which limits the improvement of their properties such as catalytic activity and stability. To address this problem, in this paper, a three-dimensional ( 3D) N-doped porous carbon (NCZIF-8) material with a large specific surface area was prepared as a catalyst carrier using ZIF-8 as a precursor. Low loading rate of platinum (10 wt. %) was prepared (10% Pt/NCZIF-8) and used as catalysts for glucose oxidation reaction. The materials were structurally characterized by XRD, SEM, TEM, Raman and FT-IR, etc. The electrocatalytic properties of the materials were characterized using an electrochemical workstation. It was shown that the incorporation of NCZIF-8 carrier promotes the dispersion of Pt nanoparticles (NPs) and the utilization of the catalyst, which enhances the catalytic activity and stability of catalysts during electrocatalytic glucose oxidation. After 300 times cyclic voltammetry (CV) tests, the peak current density of 10% Pt/NCZIF-8 only decreased by 21. 12% and 8. 59% in the double-layer region and oxygen region, respectively, indicating the excellent stability of the catalyst. This kind of catalyst with low loading rate of precious metal has great potential for its practical application by improving catalyst utilization, which not only improves the catalytic efficiency but also reduces the material cost.

Exploring Copper Oxide and Copper Sulfide for Non-Enzymatic Glucose Sensors: Current Progress and Future Directions.

Millions of people worldwide are affected by diabetes, a chronic disease that continuously grows due to abnormal glucose concentration levels present in the blood. Monitoring blood glucose concentrations is therefore an essential diabetes indicator to aid in the management of the disease. Enzymatic electrochemical glucose sensors presently account for the bulk of glucose sensors on the market. However, their disadvantages are that they are expensive and dependent on environmental conditions, hence affecting their performance and sensitivity. To meet the increasing demand, non-enzymatic glucose sensors based on chemically modified electrodes for the direct electrocatalytic oxidation of glucose are a good alternative to the costly enzymatic-based sensors currently on the market, and the research thereof continues to grow. Nanotechnology-based biosensors have been explored for their electronic and mechanical properties, resulting in enhanced biological signaling through the direct oxidation of glucose. Copper oxide and copper sulfide exhibit attractive attributes for sensor applications, due to their non-toxic nature, abundance, and unique properties. Thus, in this review, copper oxide and copper sulfide-based materials are evaluated based on their chemical structure, morphology, and fast electron mobility as suitable electrode materials for non-enzymatic glucose sensors. The review highlights the present challenges of non-enzymatic glucose sensors that have limited their deployment into the market.

Construction of Snow-Cake Like NiCo2O4 Nanostructures Modified Electrode Material and Its Electrocatalytic Oxidation of Glucose

Construction of Snow-Cake Like NiCo2O4 Nanostructures Modified Electrode Material and Its Electrocatalytic Oxidation of Glucose

Defect rich Ni/NiO-graphene heterostructures with oxygen bridges for enhanced electrocatalytic glucose oxidation towards selective sensing

Defect rich Ni/NiO-graphene heterostructures were developed by combining electrocatalytically active Ni/NiO nanocomposite with graphene sheets using a facile single step solution combustion method. The synthesised electrocatalyst was characterized using XRD, Raman, FTIR, XPS, FESEM, TEM and HRTEM techniques. Ni–O–C linkage was evidenced from XPS spectrum in concurrent with G-band shift in Raman spectrum showed the effective integration of active nanocomposite with graphene sheets. Moreover, the wide distribution of active nanocomposite material on graphene sheets with a greater number of defect sites within NiO lattices would expose catalytically active sites for electrochemical redox reaction and synergistic effects of these heterostructures on the electrochemical behaviour of Ni/NiO-GS hybrid nanocomposite employing EIS, CV and CA techniques were discussed. Excellent improvement in the Ni2+/Ni3+ redox activity and enhancement in the glucose oxidative property of Ni/NiO-GS/GCE with respect to Ni/NiO/GCE was contributed to the availability of more electrochemical active surface area and the combined effect of increased mass transport and charge transfer kinetics. The amperometry response of Ni/NiO-GS/GCE towards glucose over a wide linear range (0.5 mM–7.5 mM) with good sensitivity (696 μA mM−1 cm−2) and high correlation coefficient (0.9959) at an applied potential of about 0.495 V vs Ag/AgCl with anti-interference ability, repeatable and reproducible glucose oxidative current responds with an estimated relative standard deviation of 0.018 and 0.014 respectively makes it as a prospective electrode material for cost-effective glucose selective sensor.

Effect of Carbon Layer Thickness on the Electrocatalytic Oxidation of Glucose in a Ni/BDD Composite Electrode.

High-performance non-enzymatic glucose sensor composite electrodes were prepared by loading Ni onto a boron-doped diamond (BDD) film surface through a thermal catalytic etching method. A carbon precipitate with a desired thickness could be formed on the Ni/BDD composite electrode surface by tuning the processing conditions. A systematic study regarding the influence of the precipitated carbon layer thickness on the electrocatalytic oxidation of glucose was conducted. While an oxygen plasma was used to etch the precipitated carbon, Ni/BDD-based composite electrodes with the precipitated carbon layers of different thicknesses could be obtained by controlling the oxygen plasma power. These Ni/BDD electrodes were characterized by SEM microscopies, Raman and XPS spectroscopies, and electrochemical tests. The results showed that the carbon layer thickness exerted a significant impact on the resulting electrocatalytic performance. The electrode etched under 200 W power exhibited the best performance, followed by the untreated electrode and the electrode etched under 400 W power with the worst performance. Specifically, the electrode etched under 200 W was demonstrated to possess the highest sensitivity of 1443.75 μA cm-2 mM-1 and the lowest detection limit of 0.5 μM.

Steering the Selectivity of Electrocatalytic Glucose Oxidation by the Pt Oxidation State.

Electrocatalytic glucose oxidation can produce high value chemicals, but selectivity needs to be improved. Here we elucidate the role of the Pt oxidation state on the activity and selectivity of electrocatalytic oxidation of glucose with a new analytical approach, using high-pressure liquid chromatography and high-pressure anion exchange chromatography. It was found that the type of oxidation, i.e. dehydrogenation of primary and secondary alcohol groups or oxygen transfer to aldehyde groups, strongly depends on the Pt oxidation state. Pt0 has a 7-fold higher activity for dehydrogenation reactions than for oxidation reactions, while PtOx is equally active for both reactions. Thus, Pt0 promotes glucose dialdehyde formation, while PtOx favors gluconate formation. The successive dehydrogenation of gluconate is achieved selectively at the primary alcohol group by Pt0, while PtOx also promotes the dehydrogenation of secondary alcohol groups, resulting in more complex reaction mixtures.

Steering the Selectivity of Electrocatalytic Glucose Oxidation by the Pt Oxidation State

AbstractElectrocatalytic glucose oxidation can produce high value chemicals, but selectivity needs to be improved. Here we elucidate the role of the Pt oxidation state on the activity and selectivity of electrocatalytic oxidation of glucose with a new analytical approach, using high‐pressure liquid chromatography and high‐pressure anion exchange chromatography. It was found that the type of oxidation, i.e. dehydrogenation of primary and secondary alcohol groups or oxygen transfer to aldehyde groups, strongly depends on the Pt oxidation state. Pt0 has a 7‐fold higher activity for dehydrogenation reactions than for oxidation reactions, while PtOx is equally active for both reactions. Thus, Pt0 promotes glucose dialdehyde formation, while PtOx favors gluconate formation. The successive dehydrogenation of gluconate is achieved selectively at the primary alcohol group by Pt0, while PtOx also promotes the dehydrogenation of secondary alcohol groups, resulting in more complex reaction mixtures.

Improved electrocatalytic activity of Pt on carbon nanofibers for glucose oxidation mediated by support oxygen groups in Pt perimeter

Support effects in supported metal catalysts are well studied for thermocatalytic reactions, but less studied for electrocatalytic reactions. Here, we prepared a series of Pt supported on carbon nanofiber catalysts which vary in their Pt particle size and the content of oxygen groups on the surface of the CNF. We show that the activity of these catalysts for electrocatalytic glucose oxidation relates linearly with the content of support oxygen groups. Since the electronic state of Pt (XAS) and Pt surface structure (CO-stripping) were indistinguishable for all materials, we conclude that sorption effects of glucose play a crucial role in catalytic activity. This was further confirmed by establishing a relation between the annulus of the Pt particles and the activity.

Cu Aerogels with Sustainable Cu(I)/Cu(II) Redox Cycles for Sensitive Nonenzymatic Glucose Sensing.

Developing functional nanomaterials for nonenzymatic glucose electrochemical sensing platforms is vital and challenging from the perspective of pathology and physiology. Accurate identification of active sites and thorough investigation of catalytic mechanisms are critical prerequisites for the design of advanced catalysts for electrochemical sensing. Herein, Cu aerogels are synthesized as a model system for sensitive nonenzymatic glucose sensing. The resultant Cu aerogels exhibit good catalytic activity for glucose electrooxidation with high sensitivity and a low detection limit. Significantly, in situ electrochemical investigations and Raman characterizations reveal the catalytic mechanism of Cu-based nonenzymatic glucose sensing. During the electrocatalytic oxidation of glucose, Cu(I) is electrochemically oxidized to generate Cu(II), and the resultant Cu(II) is spontaneously reduced back to Cu(I) by glucose, achieving the sustained Cu(I)/Cu(II) redox cycles. This study provides profound insights into the catalytic mechanism for nonenzymatic glucose sensing, which provides great potential guidance for a rational design of advanced catalysts in the future.

Engineering of nickel phosphate nanodots modified copper phosphate microflowers for highly efficient glucose monitoring

Transition metal phosphates have garnered significant interest as effective electrocatalysts due to their admirable chemical stability, unique physical features, low cost and exceptional electrocatalytic properties. Here, we design for the first time, a binary metal phosphate (BMP) heteroarchitecture based on nickel phosphate nanodots supported on copper phosphate microflowers (NDTs Ni3(PO4)2@Cu3(PO4)2 MFs). The surface characterizations reveal the interconnected cross-network of vertically oriented 3D nanosheets (NSs) which leads to the self-assembly of microflowers. In addition, the Ni3(PO4)2 nanodots, with an average diameter of 2.6 nm, are uniformly distributed throughout the structure, providing greater number of active centers on the surface of the designed catalyst. Thus, the customized structure has the potential to function as an excellent electrocatalyst by providing sufficient reaction space through the highly exposed edges of 3D nanosheets, and high density active site owe to the presence of NDTs. Typically, the Cu3(PO4)2 acts as an electron mediator by facilitating the Cu2+/Cu3+ redox couple, while the Ni3(PO4)2 enhances the electrocatalytic oxidation of glucose. Thus, owing to its unique physical and chemical aspects, the NDTs Ni3(PO4)2@Cu2(PO4)2 MFs demonstrate superior electrocatalytic efficacy for glucose sensing. Thanks to the novel NDTs Ni3(PO4)2@Cu2(PO4)2 MFs BMP for offering exceptional sensitivities (2197.119 and 206.111 μA mM–1 cm–2), a wide detection range (0.009–0.491 mM and 0.491–14.83 mM), a short response time (<1 s), and a low detection limit (0.06 μM, S/N = 3). Moreover, the designed sensor presents good reproducibility, admirable stability and excellent selectivity. Thus, the NDTs Ni3(PO4)2@Cu3(PO4)2 MFs are promising for the potential applications in glucose sensor, to monitor glucose in human serum and other body fluids.

Enzymeless Electrochemical Glucose Sensors Based on Metal–Organic Framework Materials: Current Developments and Progresses

Electrochemical glucose sensors play a crucial role in medicine, bioscience, food science, and agricultural science. Metal–organic frameworks possess exceptional properties, such as large specific surface area, high porosity, tunable pore structure, high catalytic activity, open metal active sites, and structural diversity. The catalytic activity of metal–organic frameworks enables electrocatalytic oxidation of glucose without the need for enzymes. Consequently, enzymeless electrochemical glucose sensors based on metal–organic framework materials have gained much attention and have been extensively studied for glucose detection. This mini-review provides an overview of the development and progress of enzymeless electrochemical glucose detection based on metal–organic framework material–modified electrodes, including doping materials, sensitivity, detection limit, and fast response capability. With the advancement of this technology, enzymeless electrochemical glucose sensors can continuously and stably detect glucose and can be utilized in various fields, such as wearable devices.

Assist of multi-walled carbon nanotubes toward metal–organic framework chamfer cube-derived rambutan-like cobalt oxide@hollow chain and its application for non-enzymatic glucose sensing

Herein, a novel preparation strategy has been performed to obtain the highly dispersed Co3O4 nanoparticles coated hollow carbon chain (Co3O4NPs@HCC) with the aid of multi-walled carbon nanotubes (MWCNTs). Such electrode material has rambutan-like surface and hollow structure, which is derived from ZIF-67 chamfer cube chain. More importantly, the Co3O4NPs@HCC-MWCNTs exhibits excellent electrochemical performances for glucose sensing because of the highly distinguished surface structure, leading to the high-efficiency reaction interface for the non-enzymatic electrocatalytic oxidation of glucose. The sensing mechanism and structure-activity relationship of Co3O4NPs@HCC-MWCNTs have been carefully considered by the control experiments. The Co3O4NPs, HCC and MWCNTs form a novel material structure, where each part has important functions to contribute the high-performance behaviors of Co3O4NPs@HCC-MWCNTs. The established Co3O4NPs@HCC-MWCNTs-based sensor shows 0.5–100.0 μM of linear detection range (R2 = 0.99998), 43.9 nM of detection limit and 1261 μA mM−1 cm−2 of sensitivity for glucose sensing.

Ni-MOF derived rod-like nickel hydroxide through controllable hydrolysis for efficient electrocatalytic glucose oxidation

In this work, a new rod-like Ni-MOF (rNi-MOF) acted initially as an important catalyst in hydrolyzing of extrinsic Ni2+. Then rNi-MOF would also be etched by protons (the other product of hydrolysis) resulted in increasing free Ni2+ that can bond with OH− for in-situ formation of Ni(OH)2 coated on rNi-MOF. The amount of extrinsic Ni2+ and water showed significant influences on morphology of rNi-MOF/Ni(OH)2. It was found the rNi-MOF/Ni(OH)2 prepared by 4 mL water and 0.5 mmol Ni2+ exhibited excellent electrochemical performances in detection of glucose due to its high specific surface area (220 m2 g−1), abundant active Ni(II)/Ni(III) pairs. The rNi-MOF/Ni(OH)2 modified glassy carbon electrode (rNi-MOF/Ni(OH)2/GCE) exhibited a high sensitivity of 3616 μA mM−1 cm−2, the low detection of limit (0.7 μM). Moreover, the proposed modified sensor displayed a high reproducibility and stability which set a foundation for promising application in detecting of glucose in human serum with good recoveries (95 %–105 %).

ZIF-8-Derived Three-Dimensional Nitrogen-Doped Porous Carbon as a Pt Catalyst Support for Electrocatalytic Oxidation of Glucose in a Glucose Fuel Cell

ZIF-8-Derived Three-Dimensional Nitrogen-Doped Porous Carbon as a Pt Catalyst Support for Electrocatalytic Oxidation of Glucose in a Glucose Fuel Cell