Electrocatalytic Activity For Glucose Oxidation Research Articles

One-step laser-induced Cu-embedded graphene for non-enzymatic glucose sensing in beverages

The detection of glucose in beverages is crucial for dietary management and healthcare. Excessive sugar consumption can lead to severe conditions, such as obesity, diabetes, cardiovascular diseases, and cancer. In this study, Cu-embedded laser-induced graphene (Cu/LIG) materials were fabricated for non-enzymatic glucose detection using a simple, direct, and cost-effective laser-patterning method on a Cu2+/ethyl-cellulose/polyimide membrane. The experimental results showed that the Cu/LIG electrode exhibited lower charge transfer resistance and a distinct diffusion process compared to the LIG electrode. This improvement can be attributed to the optimized graphene formation achieved by employing ethyl-cellulose (EC) and CuCl2 as combustion promoters. Under optimal conditions, Cu/LIG-600 demonstrated excellent electrocatalytic activity for glucose oxidation, with a low response concentration (5 μM), fast response time (2.0 s), and detection ranges of 0.005–0.525 mM (I-t) and 0.5–4.0 mM (CV). Moreover, the sensor exhibited high selectivity, stability (retaining over 90 % activity after 28 days), and satisfactory recovery rates for spiked glucose in Cola, Sprite, Black Tea, and sugarless Soda Water, indicating its potential for non-enzymatic glucose detection in beverages.

Dual-confinement regulating ternary metal-oxide activity sites derived from Co-MOF for enhanced electrocatalytic activity for glucose oxidation

Based on a dual-confinement strategy on a cobalt-metal-organic framework (Co-MOF), a series of trimetallic-oxide catalysts of Cux-O-Niy-O-Co3-x-y (x/y = 1/1, 1/3, 1/5 and 1/7) were developed for glucose oxidation. By chemical confinement regulation of ion exchange, diverse metal catalytic sites of Cu2+ and Ni2+ were introduced into Co-MOF, respectively; Then by spatial confinement synthesis of pyrolysis, trimetallic MOF of CuxNiyCo3-x-y-MOF was transformed into trimetallic-oxide of Cux-O-Niy-O-Co3-x-y, which maintained the regular morphology and highly ordered lattice structure of Co-MOF. The Cux-O-Niy-O-Co3-x-y composite modified glassy carbon electrode (Cux-O-Niy-O-Co3-x-y/GCE) exhibited enhanced electrocatalytic activity towards glucose oxidation when compared with Co-MOF/GCE, bimetallic MOFs of CuCo-MOF/GCE and NiCo-MOF/GCE, trimetallic MOF of CuxNiyCo3-x-y-MOF/GCE, as well as monometallic oxide Co3O4/GCE and bimetallic oxides of CuCo2O4/GCE and NiCo2O4/GCE, which was mainly due to the synergistic catalysis of electrocatalytically active Co-O-Cu-O-Ni bridges. With Cu2+/Ni2+ molar ratio of 1/3, Cux-O-Niy-O-Co3-x-y/GCE (x/y = 1/3) displayed excellent sensing behaviours on glucose detection. This work not only designed well-performed electrocatalysts for enhancing catalytic activity towards glucose oxidation, but also provided a new perspective to realize the controlled preparation of high-performance electrocatalysts.

Highly Efficient Non-Enzymatic Electrochemical Glucose Biosensor Based on Copper Metal Organic Framework Coated on Graphite Sheet

Detection of glucose is highly informative, creating a constant demand for fabricating high-precision glucose biosensors. Metal–organic frameworks, a family of porous materials renowned for their tunability, can be an excellent choice for developing such sensors. We have developed a highly-sensitive, non-enzymatic sensor for electrochemical detection of glucose fabricated using Copper Metal–Organic Framework (Cu MOF), synthesized by a simple, room-temperature stirring method using Benzene-1,3,5-tricarboxylic acid (BTC) as ligand and Copper nitrate trihydrate as precursor. The synthesized nanostructure was characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, and energy-dispersive X-ray analytical techniques. Powder X-ray diffraction study and thermogravimetric analysis were also done. Further, Brunnauer-Emmett-Teller analysis revealed the porous nature of Cu MOF. The materials exhibited strong electro-catalytic activity for glucose oxidation as revealed from cyclic voltammetry and chronoamperometric studies done under alkaline pH conditions. The Cu MOF deposited on a conducting graphite sheet electrode displayed a significantly low detection limit of 0.019 mM through a broad detection range (1–15 mM) and a strong sensitivity of 229.4 μAmM−1 cm2. Overall, the Cu MOF/GS exhibits exceptional stability, short response time (less than 1 s), and good repeatability and reproducibility, making it a promising future material for non-enzymatic glucose detection.

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.

An enzyme-free Ti3C2/Ni/Sm-LDH-based screen-printed-electrode for real-time sweat detection of glucose

Here, we report the fabrication of an enzyme-free glucose sensor benefiting from nickel-samarium nanoparticles-decorated MXene layered double hydroxide (MXene/Ni/Sm-LDH). The electrochemical response of the MXene/Ni/Sm-LDH to glucose was studied via cyclic voltammetry (CV). The fabricated electrode has high electrocatalytic activity for glucose oxidation. The voltametric response of the MXene/Ni/Sm-LDH electrode to glucose was investigated by differential pulse voltammetry (DPV) that demonstrated an extended linear range of from 0.001 to 0.1 mM and 0.25–7.5 mM with a detection limit down to 0.24 μM (S/N = 3) and a sensitivity at 1673.54 μA mM−1 cm−2 1519.09 μA mM−1 cm−2 in concentrations of 0.01 mM and 1 mM respectively as well as good repeatability, high stability and applicability for the real sample analysis. Moreover, the as-fabricated sensor was applied to glucose detection in human sweat and showed promising results.

Partially Oxidized Carbon Nanomaterials with Ni/NiO Heterostructures as Durable Glucose Sensors.

Conventional enzyme-based glucose biosensors have limited extensive applications in daily life because glucose oxidase is easily inactivated and is expensive. In this paper, we propose a strategy to prepare a new type of cost-effective, efficient, and robust nonenzymatic Ni-CNT-O for electrochemical glucose sensing. It is first followed by the pyrolysis of Ni-ABDC nanostrips using melamine to grow carbon nanotubes (CNTs) to give an intermediate product of Ni-CNT, which is further accompanied by partial oxidation to enable the facile formation of hierarchical carbon nanomaterials with improved hydrophilicity. A series of physicochemical characterizations have fully proved that Ni-CNT-O is a carbon-coated heterostructure of Ni and NiO nanoparticles embedded into coordination polymer-derived porous carbons. The obtained Ni-CNT-O exhibits a better electrocatalytic activity for glucose oxidation stemming from the synergistic effect of a metal element and a metal oxide than unoxidized Ni-CNT, which also shows high performance with a wide linear range from 1 to 3000 μM. It also offers a high sensitivity of 79.4 μA mM-1 cm-2, a low detection limit of 500 nM (S/N = 3), and a satisfactory long-term durability. Finally, this glucose sensor exhibits good reproducibility, high selectivity, as well as satisfactory results by comparing the current response of simulated serum within egg albumen.

Metal-organic framework derived porous hollow ZnCo2S4 improving electrocatalytic oxidation of glucose

In this paper, ZnCo2S4 nanomaterial with a unique structure were synthesized by static and hydrothermal method and applied to the field of electrochemical sensing. Based on the advantages of metal-organic frameworks (MOF) materials with large specific surface areas, multiple active centers, and synergistic effect of multi-metals, we choose Zn and Co bimetallic MOF as the precursor material and synthesized ZnCo2S4 nanomaterials with large active area and multiple active centers after vulcanization. In addition, we verified the excellent electrochemical sensing performance of the prepared ZnCo2S4 nanomaterial through the catalytic oxidation experiment of glucose. The results showed that ZnCo2S4 nanomaterials with bimetallic MOF as a precursor had higher electrocatalytic activity for glucose oxidation than ZnCo2S4 nanomaterials without precursor and single metal sulfide. According to the analysis of the electrochemical performance of the material, the detection limit is extremely low (0.007 μM)and two linear range (3 ∼9 μM) and (10 ∼100 μM)for glucose. Therefore, we believe that the method of preparing polymetallic sulfides with MOF as a precursor is of great significance in electrochemical sensing.

Laser-induced graphene (LIG)-based Au@CuO/V2CTx MXene non-enzymatic electrochemical sensors for the urine glucose test

Glucose monitoring is of great significance for the health management of diabetic patients. Herein, non-enzymatic glucose sensors were developed by modifying Au@CuO or Au@CuO/V2CTx MXene nanocomposites (NCs) on the surface of disposable laser-induced graphene (LIG) electrode. The structures and morphologies were confirmed by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and elemental analysis. The electrochemical performances of NCs were investigated by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and chronoamperometry (CA). The results demonstrated that both Au@CuO/LIG and Au@CuO/V2CTx MXene/LIG have excellent electrocatalytic activity for glucose oxidation in an alkaline medium. However, it was found that Au@CuO/V2CTx MXene/LIG was easily oxidized. Hence, the combination of Au@CuO/LIG was preferred for glucose test. Under optimized conditions, the electrochemical sensor achieved a detection range of 0.005 to 5.0 mM with a sensitivity of 1.124 × 106 μA mM−1 cm−2. The response time was 1.5 s and the limit of detection (LOD) was as low as 1.8 μM. The sensor has good selectivity and stability (84.12 % activity retained after 6 weeks). Its affordable price, disposable usage and portable essence are suitable for clinical application. Our study presented a novel strategy to the field of non-enzymatic glucose sensing.

MOF-derived MoS2@Co3S4 nanoparticles modified with Ag as efficient sensor for glucose determination

In the present study, one-step hydrothermal route was utilized to synthesize pristine and Ag-doped MoS2@Co3S4 hollow polyhedrons from zeolitic imidazolate framework-67 (ZIF-67). The obtained structure was then used to achieve a modified electrode for glucose (GL) determination. The Ag/MoS2@Co3S4 nanohybrid was examined by XRD, TEM, FESEM, and EDX. The influence of co-presence of MoS2, Co3S4 and Ag on the electrochemical activities of MoS2@Co3S4 and Ag/MoS2 @ Co3S4 was also explored. The amperometric response of Ag/MoS2@Co3S4 modified glassy carbon electrode (GC electrode) in GL oxidation exhibited two linear ranges of (0.2 −30 µM and 50 µM – 1 mM) with limit of detection (LOD) of 0.05 µM. Compared to MoS2/GC and MoS2@Co3S4/GC electrodes, the Ag/MoS2@Co3S4/GC electrode displayed superior electrocatalytic activity for GL oxidation which can be assigned to the synergistic effect of Ag NPs. Examination of the effect of intrusive ions on the determination of analyte revealed the stability, reproducibility, and selectivity of sensor in GL determination. Accordingly, the Ag/MoS2@Co3S4 could be an effective platform for GL determination.

Pd-Decorated NiCo2O4 Nanotubes Derived from Template-Free Process for Improved Electrocatalytic Glucose Oxidation

The electrode materials for highly efficient glucose oxidation reaction (GOR) are vital for nonenzymatic glucose sensors (NEGS) and direct glucose fuel cells. The Pd-decorated NiCo2O4 nanotubes (Pd/NiCo2O4 NTs) were prepared through the template-free process. Pd/NiCo2O4 NTs presented highly improved electrocatalytic activity for glucose oxidation. When applied to glucose detection, Pd/NiCo2O4 NTs displayed superior sensing performance with a wide detection range of 5 [Formula: see text]M–9 mM. The sensitivity and detection limit are 214.2 [Formula: see text] and 1.6 [Formula: see text]M, respectively. Moreover, the Pd/NiCo2O4 NTs sensors also demonstrated excellent selectivity and feasibility for glucose detection for serum sample analysis.

A novel self-powered sensor based on Ni(OH)2/Fe2O3 photoanode for glucose detection by converting solar energy into electricity

• A photo fuel cell (PFC) based self-powered sensor is successfully constructed. • The sensing is powered by converting solar energy without external power inputting. • The glucose sensitivity is 24.59 μW cm −2 mM −1 on Ni(OH) 2 /Fe 2 O 3 self-powered sensor. • It is much higher than 3.53 μW cm −2 mM −1 obtained on bare Fe 2 O 3 based sensor. • Ni(OH) 2 enhances the charge injection and promotes glucose oxidation kinetics. Self-powered sensors have great application prospects in the field of analytic chemistry because they can determine analytes without inputting external electricity. In this work, Fe 2 O 3 electrode with nanorod morphology was synthesized by chemical bath method, then a layer of Ni(OH) 2 was decorated on the surface of Fe 2 O 3 nanorods via successive ion adsorption. Furthermore, a Ni(OH) 2 /Fe 2 O 3 -based photo fuel cell (PFC) was fabricated as a novel self-powered sensor. The produced maximum power density ( P max ) of the sensor shows a linear relationship with glucose concentrations in the range of 0.05–0.25 mM with a sensitivity of 24.59 μW cm –2 mM –1 , which is much higher than that of bare Fe 2 O 3 -based self-powered sensor (only 3.53 μW cm –2 mM –1 ). The better performance achieved on the Ni(OH) 2 /Fe 2 O 3 -based sensor is because Ni(OH) 2 has high electrocatalytic activity for glucose oxidation and it can improve photo-generated charge inject efficiency ( η inj ) to substrate. In addition, the sensor also possesses good selectivity, stability and applicability for glucose sensing. In a word, this work provides a non-enzymatic, simple-construction, cost-effective and sustainable PFC based self-powered sensor, which may guide future designs for the determination of analytes and offer a new route for utilization of widespread solar energy.

TiO2 quantum dots/reduced graphene oxide composite modified with Au for electrochemical oxidation reaction

TiO2/graphene as catalyst substrate has attracted considerable attentions in the field of electrochemistry because of the synergistic effects bring from good chemical stability of TiO2 and intrinsic superior conductivity of graphene. In this work, TiO2 quantum dots are prepared on reduced graphene (TiO2QDs/RGO) by a novel supercritical CO2 fluid assisted hydrothermal method, following, the Au–TiO2QDs/RGO electrodes are achieved by electrodepositing Au on the TiO2QDs/RGO support. The obtained Au–TiO2QDs/RGO shows better electrocatalytic activity for glucose oxidation than the electrodes of Au-RGO, Au–P25 (commercial TiO2) and Au-Mixed P25/RGO. Specially, the lower the loading of Au, the more significant in performance of Au–TiO2QDs/RGO distinguishes from other three electrodes. The high activity is probably owing to the synergistic catalytic effects of TiO2QDs and Au, the quantum-sized TiO2QDs, as well as the co-substrate of RGO. All of these are beneficial to electron transfer and the release of poisoning intermediates thus promote the electrocatalytic oxidation of glucose. The study might offer some new clues for designing efficient hybrid catalysts in applications of electrocatalysis and energy conversion/storage.

Cu-Based Conductive MOF Grown in situ on Cu Foam as a Highly Selective and Stable Non-Enzymatic Glucose Sensor.

A non-enzymatic electrochemical sensor for glucose detection is executed by using a conductive metal–organic framework (MOF) Cu-MOF, which is built from the 2,3,6,7,10,11-hexahydroxytriphenylene (HHTP) ligand and copper acetate by hydrothermal reaction. The Cu-MOF demonstrates superior electrocatalytic activity for glucose oxidation under alkaline pH conditions. As an excellent non-enzymatic sensor, the Cu-MOF grown on Cu foam (Cu-MOF/CF) displays an ultra-low detection limit of 0.076 μM through a wide concentration range (0.001–0.95 mM) and a strong sensitivity of 30,030 mA μM−1 cm−2. Overall, the Cu-MOF/CF exhibits a low detection limit, high selectivity, excellent stability, fast response time, and good practical application feasibility for glucose detection and can promote the development of MOF materials in the field of electrochemical sensors.

Automatic processing technology based on nanomaterials

Nanotechnology refers to technology that studies the performance and usage of materials with a structure size of 0.1 to 100 nanometers. Due to the special size of this material, it determines that this material has many more special properties than ordinary materials, such as size effect, surface effect, etc., so its application market can be said to be very broad. At present, the application of nanomaterials in daily production and life has aroused widespread concern, especially the two major blocks of biology and medicine. How to combine different properties such as magnetism and catalytic properties to form multifunctional nanomaterials and how to use the material more efficiently in the field of biology has become a research direction of experts. Machine learning can realize the automatic identification of non-good wood, which effectively avoids the impact of visual fatigue or other subjective factors in the manual identification process, and machine learning has a more accurate positioning of the standard of non-good wood, thereby improving the wood's quality. Usage rate. In this paper, the fuzzy analytic hierarchy process is mainly used to study the catalytic performance of nanocomposites on glucose oxidation. Compared with glassy carbon bare electrode (GCE) and IL-GR / GCE, / IL-GR / GCE showed significant electrocatalytic activity for glucose oxidation. The linear range is 0 ∼ 1000 μM, and the detection limit is 0.162 μM (S / N = 4). The results showed that the current response of glucose did not change significantly, proving that / IL-GR / GCE has a strong anti-interference ability.

Green fabrication of Cu/rGO decorated SWCNT buckypaper as a flexible electrode for glucose detection

As a paper-like membrane composed of single-walled carbon nanotube (SWCNT), buckypaper possesses high conductivity, ideal flexibility, large surface area, great thermal/chemical stability and biocompatibility, which has manifested its potential as an alternative support material. However, due to the lack of defects, high quality SWCNT synthesized by arc-discharge method is difficult to be modified with metal nanoparticles for electro-catalysis. In this paper, a novel green strategy has been developed to fabricate SWCNT buckypaper decorated with Cu/reduced graphene oxide (Cu/rGO-BP) for the first time, in which graphene oxide functions as the intermediate between SWCNT and Cu nanoparticles. The fabricated Cu/rGO-BP was applied as a flexible electrode for electrochemical glucose detection. The electrode exhibited excellent electro-catalytic activity for glucose oxidation. The sensor based on Cu/rGO-BP performed a high upper limit of linear range (25 mM), which is close to commercial glucose sensors. The proposed strategy for Cu/rGO-BP fabrication can be extended to modify buckypaper with other metal or metal oxide nanoparticles, and thus opens an innovative route to potential practical applications of flexible buckypaper in wearable bioelectronics.

Correction to Facile Synthesis of Ultrathin Nickel-Cobalt Phosphate 2D Nanosheets with Enhanced Electrocatalytic Activity for Glucose Oxidation.

RETURN TO ISSUEPREVAddition/CorrectionNEXTORIGINAL ARTICLEThis notice is a correctionCorrection to Facile Synthesis of Ultrathin Nickel–Cobalt Phosphate 2D Nanosheets with Enhanced Electrocatalytic Activity for Glucose OxidationYun ShuYun ShuMore by Yun Shu, Bing LiBing LiMore by Bing Li, Jingyuan ChenJingyuan ChenMore by Jingyuan Chen, Qin XuQin XuMore by Qin Xu, Huan PangHuan PangMore by Huan Panghttp://orcid.org/0000-0002-5319-0480, and Xiaoya Hu*Xiaoya HuMore by Xiaoya Huhttp://orcid.org/0000-0002-8061-5165Cite this: ACS Appl. Mater. Interfaces 2020, 12, 26, 30018Publication Date (Web):June 17, 2020Publication History Published online17 June 2020Published inissue 1 July 2020https://doi.org/10.1021/acsami.0c09482Copyright © 2020 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views445Altmetric-Citations-LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (398 KB) Get e-Alerts Get e-Alerts

MOF-derived ZnCo2O4 porous micro-rice with enhanced electro-catalytic activity for the oxygen evolution reaction and glucose oxidation.

A porous ZnCo2O4 micro-rice like microstructure was synthesized via calcination of a Zn–Co MOF precursor at an appropriate temperature. The as-prepared ZnCo2O4 sample presented good electrocatalytic oxygen evolution reaction performance with a small overpotential (η10 = 389 mV) and high stability in basic electrolyte. Furthermore, in basic medium, the as-synthesized ZnCo2O4 micro-rice also showed good electrocatalytic activity for glucose oxidation. A ZnCo2O4 micro-rice modified glass carbon electrode may be used as a potential non-enzymatic glucose sensor. The excellent electrocatalytic OER and glucose oxidation performances of ZnCo2O4 might be attributed to the unique porous structure formed by the nanoparticles. The porous architecture of the micro-rice can provide a large number of electrocatalytically active sites and high electrochemical surface area (ECSA). The result may offer a new way to prepare low-cost and high performance oxygen evolution reaction and glucose oxidation electrocatalysts.

Self-template formation of porous Co3O4 hollow nanoprisms for non-enzymatic glucose sensing in human serum.

A novel type of porous Co3O4 hollow nanoprism (HNP) was successfully prepared using tetragonal cobalt acetate hydroxide [Co5(OH)2(OAc)8·2H2O] as precursor by a facile solvothermal process and a subsequent calcination treatment. The morphology and structure of the Co3O4 HNPs were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), powder X-ray diffraction (XRD) and N2 adsorption–desorption measurements. An enzyme-free glucose sensor was constructed based on the Co3O4 HNPs, and the electrochemical performance was tested by cyclic voltammetry (CV) and chronoamperometry. The as-prepared sensor exhibited a good electrocatalytic activity for glucose oxidation at the applied potential of 0.6 V in alkaline solution, with a high sensitivity of 19.83 μA mM−1 cm−2 and a high upper limit of 30 mM, which provide the potential for direct determination of blood glucose without any dilution pretreatment. The Co3O4 HNPs had a porous and tubular structure with a large amount of accessible active sites, which enhanced the mass diffusion and accelerated the electron transfer. Moreover, the sensor also demonstrated a desirable stability, selectivity and reproducibility, and could verify the non-enzymatic analysis of glucose in real samples.

Preparation of Asparagus-Shaped CuO Nanostructures and Their Electrocatalytic Activity for Glucose Oxidation

Asparagus-shaped CuO nanostructures were prepared by hydrothermal method using CuCl2·2H2O and NaOH as raw materials, using CTAB as surfactant. The effects of various factors such as the reaction temperature, the surfactant addition amount and the reactants concentration on the CuO crystal phase were studied by X-ray diffraction. The composition and morphology were characterized by Fourier Transform Infrared (FT-IR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM). A glassy carbon electrode (GCE) modified by asparagus-shaped CuO nanostructures was used as the working electrode, the Ag/AgCl electrode was used as the reference electrode, and Pt wire electrode was used as the auxiliary electrode, the electrocatalytic activity for glucose was tested in a three-electrode system. Cyclic voltammetry (CV) curves show that the redox peak current of 0.1 M NaOH electrolyte with glucose is larger than that of NaOH without glucose, indicating that asparagus-shaped CuO nanostructures have good catalytic oxidation performance for glucose. The mechanism of electrocatalytic oxidation of glucose has been proposed.