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1.
The hierarchical three-dimensional nitrogen-doped carbon nanotube anchored bimetallic cobalt copper organic framework (NCNT MOF CoCu) is successfully synthesized by the direct growth approach using the high-temperature carbonization of bimetallic cobalt copper organic framework (MOF CoCu-500). The as-prepared NCNT MOF CoCu nanostructure possesses high-level activity for both glucose and hydrogen peroxide (H 2O 2) sensing molecules. The cyclic voltammetry (CV) and chronoamperometry (CA) studies demonstrate excellent electrocatalytic performance for the oxidation of glucose with a linear range of 0.05 to 2.5 mM, high sensitivity of 1027 μA mM −1cm −2, and the lowest detection limit of 0.15 μM. Similarly, the NCNT MOF CoCu nanostructure showed significantly higher H 2O 2 activity with a linear range of 0.05 to 3.5 mM, high sensitivity of 639.5 μA mM −1cm −2, and the lowest detection limit of 0.206 μM. Thanks to its special hierarchical nanoarchitecture, homogeneous nitrogen-doped carbon nanotubes, and highly graphitized carbon, which may be increased the synergistic effect between bimetallic CoCu and NCNT in the organic framework. The potentially effective fabricated sensor was also used as a suitable probe for the detection of glucose and H 2O 2 in the analysis of the real samples. 相似文献
2.
Nanomaterials with enzyme-like activities, termed as nanozymes, have found wide applications in various fields. It has been a long-term aim to rationally design and synthesize highly active nanozymes and thus to further improve their application performance. Guided by the nanoconfinement effect, we confine cytochrome c (Cyt c) within a mesoporous metal–organic framework (MOF), PCN-222 nanoparticle (NP), forming a protein/MOF hybrid nanozyme, termed as Cyt c@PCN-222 NP. The confined Cyt c exhibits around 3–4-fold higher peroxidase-like activity than free Cyt c. Due to the increase in the activity of Cyt c, the Cyt c@PCN-222 NPs exhibit a quite low limit of detection (≈0.13 μM) towards H 2O 2. Sonication-induced H 2O 2 formation in water by using a lab-quipped ultrasonic cleaner can be sensitively probed, which suggests that H 2O 2-sensitive materials should be carefully handled during the utilization of ultrasonic equipment. We speculate that this nanoconfinement strategy can broaden our synthetic methodology for the rational design of nanozymes. 相似文献
3.
Ag/MnO 2/GO nanocomposites were synthesized via the method of gas/liquid interface based on silver mirror reaction, and a non‐enzymatic H 2O 2 sensor was fabricated through immobilizing Ag/MnO 2/GO nanocomposites on GCE. The composition and morphology of the nanocomposites were studied by energy‐dispersive X‐ray spectroscopy (EDS), X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). Electrochemical investigation indicated that it exhibited a favorable performance for the H 2O 2 detection. Its linear detection range was from 3 μM to 7 mM with a correlation coefficient of 0.9960; the sensitivity was 105.40 μA mM ?1 cm ?2 and the detection limit was estimated to be 0.7 μM at a signal‐to‐noise ratio of 3. 相似文献
4.
A novel strategy to fabricate hydrogen peroxide (H 2O 2) sensor was developed by electrodepositing palladium? silver nanoparticles (NPs) on a glassy carbon electrode. The morphology of the modified electrode was characterized by Scanning electron microscopy (SEM). The result of electrochemical experiments showed that such constructed sensor had a favorable catalytic ability, high sensitivity, excellent selectivity towards reduction of hydrogen peroxide (H 2O 2). The response to H 2O 2 is linear in the range between 0.30 μM to 2.50 mM, and the detection limit is 0.1 μM (at an S/N of 3). 相似文献
5.
A novel nanocomposite electrode based on hierarchical 3D porous MnO 2?TiO 2 for the application in hydrogen peroxide (H 2O 2) sensors has been explored. This electrode was fabricated by growing TiO 2 cross‐linked nanowires on a commercial fluorine tin oxide (FTO) glass via a hydrothermal process and subsequent deposition of 3D honeycomb‐like MnO 2 nanowalls using an electrodeposition method (denoted as 3D MNS‐TNW@FTO). The obtained 3D MNS‐TNW@FTO electrode was characterized by scanning electron microscopy (SEM), Raman spectroscopy, X‐ray diffraction (XRD), and X‐ray photoelectron spectroscopy (XPS). Based on such a unique 3D porous framework and the existence of MnO 2, the electrode demonstrates a good performance in the detection of H 2O 2, with two linear ranges from 9.8 to 125 μM and 125 μM–1.0 mM, a good selectivity of 8.02 μA mM ?1 cm ?2, and a low detection limit of 4.5 μM. In addition, the simplicity of the developed low‐cost fabrication process provides an efficient method for the mass production of electrocatalytical MnO 2?TiO 2 nanocomposites on commercial FTO glass for H 2O 2 sensing applications and can be adapted for other electrochemical sensors for various biochemical targets. It thus is beneficial for the practical usage in bioanalysis. 相似文献
6.
Urchin‐like Ag nanowires were prepared by reacting AgNO 3(aq) with Cu metal in the presence of cetyltrimethylammonium chloride and HNO 3(aq) on a screen printed carbon electrode at room temperature. The diameters of the nanowires were about 100 nm, while the lengths were up to 10 μm. Cyclic voltammetric experiments using the Ag nanowires as the working electrode showed electrocatalytic H 2O 2 reduction. The electrode exhibited a high sensitivity of 4705 μA mM ‐1 mg ‐1 cm ‐2 from 50 μM to 10.35 mM and a measurable detection limit of 10 μM in amperometric detection. This is the first report on Ag NWs for non‐enzymatic H 2O 2 sensing. 相似文献
7.
Cooperative cluster metalation and ligand migration were performed on a Zr‐MOF, leading to the isolation of unique bimetallic MOFs based on decanuclear Zr 6M 4 (M=Ni, Co) clusters. The M 2+ reacts with the μ 3‐OH and terminal H 2O ligands on an 8‐connected [Zr 6O 4(OH) 8(H 2O) 4] cluster to form a bimetallic [Zr 6M 4O 8(OH) 8(H 2O) 8] cluster. Along with the metalation of Zr 6 cluster, ligand migration is observed in which a Zr–carboxylate bond dissociates to form a M–carboxylate bond. Single‐crystal to single‐crystal transformation is realized so that snapshots for cooperative cluster metalation and ligand migration processes are captured by successive single‐crystal X‐ray structures. In 3+ was metalated into the same Zr‐MOF which showed excellent catalytic activity in the acetaldehyde cyclotrimerization reaction. This work not only provides a powerful tool to functionalize Zr‐MOFs with other metals, but also structurally elucidates the formation mechanism of the resulting heterometallic MOFs. 相似文献
8.
Abstract Simple and rapid chemiluminescence (CL) assays for H 2O 2, ?OH, ?O 2 ? and 1O 2 using 5-amino-2,3-dihydro-1,4-phthalazinedione (luminol) or 2-methyl-6-phenyl-3,7-dihydroimidazo[1,2-α]pyrazin-3-one (CLA) as CL reagents were developed. The means of the intra-assay relative standard deviations of ten replicate measurements of H 2O 2 (25-120 μM), ?OH generated from Fe(II) ion (2.5-10 μM) in the presence of 980 μM H 2O 2, ?O 2 ? generated from hypoxanthine (HX) (7-50 μM) in the presence of 9 × 10 ?3 units xanthine oxidase (XO) and 1O 2 generated from NaOCl (3-12 mM) in the presence of 97.6 μM H 2O 2 were found to be 4.0%, 2.8%, 2.4% and 8.7%, respectively. To validate the proposed methods, the scavenging abilities of three standard antioxidative compounds, such as L-ascorbic acid, (±)-α-tocopherol and superoxide dismutase (SOD) were examined for four active oxygen species and compared with those by anelectron spin resonance (ESR) spin-trapping method. In addition, the CL methods were also applied to establish the relationships between the decrease of CL intensity and the structures as well as redox characters of syringic acid, 3-hydroxybenzoic acid, 3,4-dihydroxybenzoic acid. From the obtained results, the scavenging effects to H 2O 2, ?OH, ?O 2 ? and 1O 2 of other dihydroxybenzoic acids were also evaluated. 相似文献
9.
In this paper, self‐assembled Prussian blue nanoparticles (PBNPs) on carbon ceramic electrode (CCE) were developed as a high sensitive hydrogen peroxide (H 2O 2) electrochemical sensor. The PBNPs film was prepared by a simple dipping method. The morphology of the PBNPs‐modified CCE was characterized by scanning electron microscopy (SEM). The self‐assembled PB film exhibited sufficient mechanical, electrochemical stability and high sensitivity in compare with other PB based H 2O 2 sensors. The sensor showed a good linear response for H 2O 2 over the concentration range 1 μM–0.26 mM with a detection limit of ca. 0.7 μM ( S/ N=3), and sensitivity of 754.6 mA M ?1 cm ?2. This work demonstrates the feasibility of self‐assembled PBNPs‐modified CCE for practical sensing applications. 相似文献
10.
Herein, we developed a partially controlled pyrolysis strategy to create evenly distributed NiO nanoparticles within NiFe‐MOF nanosheets (MOF NSs) for electrochemical synthesis of H 2O 2 by a two‐electron oxygen reduction reaction (ORR). The elemental Ni can be partially transformed to NiO and uniformly distributed on the surface of the MOF NSs, which is crucial for the formation of the particular structure. The optimized MOF NSs‐300 exhibits the highest activity for ORR with near‐zero overpotential and excellent H 2O 2 selectivity (ca. 99 %) in 0.1 m KOH solution. A high‐yield H 2O 2 production rate of 6.5 mol g cat?1 h ?1 has also been achieved by MOF NSs‐300 in 0.1 m KOH and at 0.6 V (vs. RHE). In contrast to completely pyrolyzed products, the enhanced catalytic activities of partially pyrolyzed MOF NSs‐300 originates mainly from the retained MOF structure and the newly generated NiO nanoparticles, forming the coordinatively unsaturated Ni atoms and tuning the performance towards electrochemical H 2O 2 synthesis. 相似文献
11.
Much effort has been devoted to photocatalytic production of hydrogen peroxide (H 2O 2) as an alternative to fossil fuels. From an economic point of view, reductive synthesis of H 2O 2 from O 2 coupled with the oxidative synthesis of value‐added products is particularly interesting. We herein report application of MIL‐125‐NH 2, a photoactive metal–organic framework (MOF), to a benzylalcohol/water two‐phase system that realized photocatalytic production and spontaneous separation of H 2O 2 and benzaldehyde. Hydrophobization of the MOF enabled its separation from the aqueous phase. This resulted in enhanced photocatalytic efficiency and enabled application of various aqueous solutions including extremely low pH solution which is favorable for H 2O 2 production but fatal to MOF structure. In addition, a highly concentrated H 2O 2 solution was obtained by simply reducing the volume of the aqueous phase. 相似文献
12.
Developing artificial enzyme mimetics for the detection of small biomolecules are a current research interest because natural enzymes bear some serious disadvantages, such as their catalytic activity can be easily inhibited and they can be digested by proteases. Herein, a heteropoly acids (HPA) encapsulating metal–organic framework (MOF) with metal-carbene structure, [Cu10(H3trz)4(Htrz)4][PMo12VO41] (PMA-MOF) as bifunctional enzyme-mimetic catalyst for colorimetric detection of hydrogen peroxide (H2O2) and ascorbic acid (AA) was designed and synthesized. Thanks to the good stability and the synergistic effect of PMA and MOF, PMA-MOF exhibits the lower limit of detection (0.222 μM towards H2O2 and 0.0046 μM to AA), and the smaller Km value (0.0138 mM for H2O2 and 0.136 mM for o-phenylenediamine) compared to most reported MOF- and HPA-based enzyme-mimetic catalyst, to the best our knowledge. 相似文献
13.
In this study, inorganic/organic composites containing poly (N‐isopropylacrylamide) coated core‐shell SiO 2 microspheres were prepared via surface‐initiated atom transfer radical polymerization (ATRP). The thermal responsive polymer, N‐isopropylacrylamide was treated with methanol, water and CuBr/CuBr 2/1,1,4,7,7‐pentamethyldiethylenetriamine (PMDETA) at room temperature to form PNIPAM@SiO 2 microspheres. The as‐prepared PNIPAM@SiO 2 microspheres were characterized by FT‐IR, TGA, XPS, SEM, TEM analyses. Hemoglobin (Hb) was immobilized onto the surfaces of PNIPAM@SiO 2 microspheres via hydrophobic and π‐π stacking interactions. The as‐prepared Hb/PNIPAM@SiO 2 electrode exhibits well‐defined redox peak at a formal potential of −0.38 V, validating the direct electrochemistry of Hb. The Hb immobilized composite film retained its bioelectroactivity without any significant loss of catalytic activity. The modified electrode detects H 2O 2 over a wide linear concentration range (0.1 μM to 333 μM) with a detection limit of 0.07 μM. This modified electrode also successfully detects H 2O 2 from food and disinfectant samples with appreciable recovery values, validating its practicality. We believe that PNIPAM@SiO 2 composite has great potential to be used in the detection of H 2O 2 and development of other enzyme based biosensors. 相似文献
14.
The nanocomposites of Ag nanoparticles supported on Cu 2O were prepared and used for fabricating a novel nonenzymatic H 2O 2 sensor. The morphology and composition of the nanocomposites were characterized using the scanning electron microscope (SEM), transmission electron microscope (TEM), energy‐dispersive X‐ray spectrum (EDX) and X‐ray diffraction spectrum (XRD). The electrochemical investigations indicate that the sensor possesses an excellent performance toward H 2O 2. The linear range is estimated to be from 2.0 μM to 13.0 mM with a sensitivity of 88.9 μA mM ?1 cm ?2, a response time of 3 s and a low detection limit of 0.7 μM at a signal‐to‐noise ratio of 3. Additionally, the sensor exhibits good anti‐interference. 相似文献
15.
Herein, we developed a partially controlled pyrolysis strategy to create evenly distributed NiO nanoparticles within NiFe-MOF nanosheets (MOF NSs) for electrochemical synthesis of H 2O 2 by a two-electron oxygen reduction reaction (ORR). The elemental Ni can be partially transformed to NiO and uniformly distributed on the surface of the MOF NSs, which is crucial for the formation of the particular structure. The optimized MOF NSs-300 exhibits the highest activity for ORR with near-zero overpotential and excellent H 2O 2 selectivity (ca. 99 %) in 0.1 m KOH solution. A high-yield H 2O 2 production rate of 6.5 mol g cat−1 h −1 has also been achieved by MOF NSs-300 in 0.1 m KOH and at 0.6 V (vs. RHE). In contrast to completely pyrolyzed products, the enhanced catalytic activities of partially pyrolyzed MOF NSs-300 originates mainly from the retained MOF structure and the newly generated NiO nanoparticles, forming the coordinatively unsaturated Ni atoms and tuning the performance towards electrochemical H 2O 2 synthesis. 相似文献
16.
A facile and green electrochemical method for the fabrication of three‐dimensional porous nitrogen‐doped graphene (3DNG) modified electrode was reported. This method embraces two consecutive steps: First, 3D graphene/polypyrrole (ERGO/PPy) composite was prepared by electrochemical co‐deposition of graphene and polypyrrole on a gold foil. Subsequently, the ERGO/PPy composite modified gold electrode was annealed at high temperature. Thus 3DNG modified electrode was obtained. Scanning electron microscopy (SEM), X‐ray photoelectron spectroscopy (XPS) and Raman spectroscopy were used to characterize the structure and morphology of the electrode. The electrode exhibits excellent electroanalytical performance for the reduction of hydrogen peroxide (H 2O 2). By linear sweep voltammetric measurement, the cathodic peak current was linearly proportional to H 2O 2 concentration in the range from 0.6 μM to 2.1 mM with a sensitivity of 1.0 μA μM −1 cm −2. The detection limit was ascertained to be 0.3 μM. The anti‐interference ability, reproducibility and stability of the electrode were carried out and the electrode was applied to the detection of H 2O 2 in serum sample with recoveries from 98.4 % to 103.2 %. 相似文献
17.
In this study, a laser‐induced graphene (LIG) loaded platinum nanoparticles (PtNPs) was prepared for precise, rapid and non‐enzymatic electrochemical detection of hydrogen peroxide (H 2O 2). The commercial PI films were used as the substrate of LIG. In order to improve the electrochemical performance of LIG, a layer of PtNPs catalyst was fabricated through a magnetron sputtering process on the surface of LIG (PtLIG). Under optimized conditions, a linear relationship between H 2O 2 reduction current and H 2O 2 concentration was recorded, the correlation coefficient R 2 is 0.9919 with the detection limit of 0.1 μM (S/N=3) and the sensitivity of 248.4 μA mM ?1cm ?2. Moreover, the PtLIG exhibits excellent selectivity, reproducibility and repeatability. Because of these remarkable advantages, we believe that PtLIG will provide a wider range of applications in biosensors and bioelectronic devices. 相似文献
18.
A Pt nanoparticle modified Pencil Graphite Electrode (PGE) was proposed for the electrocatalytic oxidation and non‐enzymatic determination of H 2O 2 in Flow Injection Analysis (FIA) system. Platinum nanoparticles (PtNPs) electrochemically deposited on pretreated PGE (p.PGE) surface by recording cyclic voltammograms of 1.0 mM of H 2PtCl 6 solution in 0.10 M KCl at scan rate of 50 mV s −1 for 30 cycles. Cyclic voltammograms show that the oxidation peak potential of H 2O 2 shifts from about +700 mV at bare PGE to +50 mV at PtNPs/p.PGE vs. Ag/AgCl /KCl (sat.). It can be concluded that PtNPs/p.PGE exhibits a good electrocatalytic activity towards oxidation of H 2O 2. Then, FI amperometric analysis of H 2O 2 was performed under optimized conditions using a new homemade electrochemical flow cell which was constructed for PGE. Linear range was found as 2.5 μM to 750.0 μM H 2O 2 with a detection limit of 0.73 μM (based on S b/m of 3). As a result, this study shows the first study on the FI amperometric determination of H 2O 2 at PtNPs/p.PGE which exhibits a simple, low cost, commercially available, disposable sensor for H 2O 2 detection. The proposed electrode was successfully applied to determination of H 2O 2 in real sample. 相似文献
19.
In this study, the first application of a capillary zone electrophoresis‐electrochemical detection (CE‐ECD) method for concurrent determination of hydrogen peroxide (H 2O 2) and ascorbic acid (AA), was developed using the Pt nanoparticles (PtNPs) modified Pt micro‐disk electrode (PtME). The electrocatalytic activity of the modified electrode for H 2O 2 and AA was characterized by cyclic voltammetry. Under optimized experimental conditions, highly linear calibration plots were observed for both H 2O 2 and AA, with concentration linear ranges of 0.8 μM to 0.8 mM and 1.0 μM to 0.8 mM. Detection limits of 0.2 μM H 2O 2 and 0.5 μM AA were determined on the basis of the signal‐to‐noise characteristics (S/N=3) of an electropherogram. Compared with the unmodified PtME, the sensitivity was promoted in that PtNPs/PtME provided an increased effective electrode surface and high catalytic activity toward H 2O 2 and AA. Using this method, the added H 2O 2 and AA in Mizone, a kind of functional drink, were detected, and the concentration of AA was found to be 2.33 mM ( n =3). The recovery rates were 95.3 % for H 2O 2 and 98.7 % for AA. The novel approach provided a wide linear range, low detection limit, good reproducibility and stability. It will provide a new insight into the balance of reactive oxygen species and antioxidant in biological systems. 相似文献
20.
A new kind of gold nanoparticles/self-doped polyaniline nanofibers (Au/SPAN) with grooves has been prepared for the immobilization of horseradish peroxidase (HRP) on the surface of glassy carbon electrode (GCE). The ratio of gold in the composite nanofibers was up to 64%, which could promote the conductivity and biocompatibility of SPAN and increase the immobilized amount of HRP molecules greatly. The electrode exhibits enhanced electrocatalytic activity in the reduction of H 2O 2 in the presence of the mediator hydroquinone (HQ). The effects of concentration of HQ, solution pH and the working potential on the current response of the modified electrode toward H 2O 2 were optimized to obtain the maximal sensitivity. The proposed biosensor exhibited a good linear response in the range from 10 to 2000 μM with a detection limit of 1.6 μM (S/N = 3) under the optimum conditions. The response showed Michaelis–Menten behavior at larger H 2O 2 concentrations, and the apparent Michaelis–Menten constant K m was estimated to be 2.21 mM. The detection of H 2O 2 concentration in real sample showed acceptable accuracy with the traditional potassium permanganate titration. 相似文献
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