Yufan Zhang

Facile synthesis of metal-organic frameworks/ordered mesoporous carbon composites with enhanced electrocatalytic ability for hydrazine

The cooper-based metal-organic frameworks (Cu-MOFs) loaded on ordered mesoporous carbon (OMC) hybrids has been synthesized by a simple and rapid method for the first time. The composite materials were characterized comprehensively by SEM, X-ray diffraction, Fourier transform infrared, nitrogen adsorption method, etc. The as-prepared novel Cu-MOFs/OMC nanohybrids extend the applications of support materials and provide new features of electrocatalytic activities. Hydrazine is performed as an electrochemical probe, which showed low limit of detection, wide linear range, and high sensitivity. The successful fabrication of Cu-MOFs/OMC holds great promise for the design of electrochemical sensors, and is a promising material to promote the development of new electrode materials.

Microwave-assisted route for the preparation of Pd anchored on surfactant functionalized ordered mesoporous carbon and its electrochemical applications

A microwave-assisted route for rapidly synthesizing Pd nanoparticles assembled on sodium dodecyl sulphate (SDS)-functionalized ordered mesoporous carbon (Pd-SOMC) hybrid nanocomposites has been reported. The formation of the composite materials was verified by detailed characterization (e.g., energy-dispersive X-ray spectra, X-ray photoelectron spectroscopy, X-ray diffraction, electrochemical impedance spectroscopy and TEM). TEM images reveal that the Pd nanoparticles with an average size of ∼3.82 nm are uniformly dispersed on the surface of OMC. The novel nanohybrids of Pd-SOMC can provide new features of electro-catalytic activities, because of the synergetic effects of Pd nanoparticles and OMC materials. The successful fabrication of Pd-SOMC holds great promise for the design of electrochemical sensors, and is a promising way to promote the development of new electrode materials.

Electrochemical study of acetaminophen oxidation by gold nanoparticles supported on a leaf-like zeolitic imidazolate framework

Decoration of leaf-like zeolitic imidazolate framework (ZIF-L) with Au nanoparticles (NPs) by a simple self-assembly method was described in this work. The materials were characterized by Fourier transform infrared spectroscopy, energy-dispersive X-ray spectra, N2 adsorption, and thermogravimetric analysis. Acetaminophen (AP) is most commonly referred to as an over-the-counter antipyretic and analgesic, which is a key factor in relieving fever and pain. It is particular significant to take efforts and conduct research for the development of reliable methods to detect the AP. An electrochemical sensor for AP was constructed based on the Au/ZIF-L, which exhibited excellent electrocatalytic activity for the oxidation of AP with the catalytic rate constant (kcat) of 4.27u202f×u202f104u202fM-1u202fs-1 and diffusion coefficient (D) of of 8.31u202f×u202f10-5u202fcm2u202fs-1. Importantly, Au/ZIF-L was developed as an effective sensing platform for the detection of AP, which showed high analytical performance, such as a linear range of 3.50u202fμM-0.056u202fmM with sensitivity of 37.28u202fμAu202fmM-1, a linear range of 0.056-0.56u202fmM with sensitivity of 25.10u202fμAu202fmM-1, and a low limit of detection of 1.02u202fμM. The successfully fabricated Au/ZIF-L device can be used to accurately measure the amount of AP in pharmaceutical samples. Results implied the potential application of functionalized MOF composite materials in the field of electrocatalysis, making it particularly suitable for electroanalytical chemistry.

Facile and green decoration of Pd nanoparticles on macroporous carbon by polyoxometalate with enhanced electrocatalytic ability

A well-defined Pd nanoparticles@polyoxometalates/macroporous carbon (Pd@POMs/MPC) tri-component nanohybrid has been developed using a facile, green, and one-pot synthesis method. The polyoxometalates were used as both reductant and bridging molecules. The novel nanohybrids of Pd@POMs/MPC can provide new features for electro-catalytic applications, because of the synergetic effects of Pd nanoparticles and MPC materials. The successful fabrication of Pd@POMs/MPC holds great promise for the design of electrochemical sensors, and is a promising material to promote the development of new electrode materials.

Novel left-handed double-helical chiral carbon nanotubes for electrochemical biosensing study

Novel left-handed double-helical chiral carbon nanotubes (CCNTs) were one-step synthesized by carbonization of self-assembled chiral polypyrrole nanotubes, which came from the electrostatic interaction between carboxylic amphiphilic molecules and pyrrole monomers. Different samples were prepared through changing the carbonization temperature. These samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), N2 adsorption–desorption and X-ray photoelectron spectroscopy (XPS). We present the electrochemical biosensing performance of the prepared CCNTs by using dopamine (DA), ascorbic acid (AA), uric acid (UA), H2O2 and NADH as probes. CCNTs show high electrocatalytic activity towards the above molecules with a decrease of overpotential and a drastic enhancement of the anodic currents compared to ordinary carbon nanotubes. Moreover, the influence of carbonization temperature, pore size, different N-bonding configurations (pyridinic N, pyrrolic N and graphitic N) and surface area on electrocatalytic performance of the CCNTs was studied in detail. The results show that CCNT-900 with the largest BET surface area and suitable N-bonding configurations exhibits the best electrocatalytic activity. CCNTs with remarkable electrochemical biosensing capability may be a kind of promising nanomaterial for electrochemical biosensing applications.

Novel potential type electrochemical chiral recognition biosensor for amino acid

AbstractNovel potential type electrochemical chiral biosensing system with unique capability of distinguishing and quantitating of tyrosine (Tyr) enantiomers by L-cysteic acid and left-handed chiral carbonaceous nanotubes (L-CCNT) modified glassy carbon electrode (L-Cys/L-CCNT/GCE) was first developed. The effect of sweep cycles of L-Cys and the kinds of L-CCNT on electrochemical chiral biosensing performance of L-Cys/L-CCNT/GCE were investigated. The electrochemical identification and quantitative determination of L- and D-tyrosine in their mixed solution were successfully achieved based on the different oxidation potential signals. The chiral structure of L-CCNT, the aromatic ring of Tyr, and also the intermolecular hydrogen bond between cysteic acid (CyA) and Tyr could possibly produce the difference in the free energy, which reflects as potential difference of L- and D-tyrosine. A good linear relationship between the potential, current, and different concentration ratios of L- and D-Tyr was obtained. Our present work realizes the simultaneous detection of Tyr enantiomers in their mixed solution based on the different potential signals, and it is of far-reaching significance in real electrochemical chiral biosensor study.n Graphical abstractConstruction of chiral recognition interface and the chiral biosensing mechanism for L-Tyr and D-Tyr

Simple synthesis of nitrogen doped graphene/ordered mesoporous metal oxides hybrid architecture as high-performance electrocatalysts for biosensing study

In the present work, a nitrogen doped graphene/ordered mesoporous metal oxides hybrid architecture (OMM-NGR) was prepared by a convenient procedure for the first time. During the preparation process, nitrogen doping, graphene reduction and ordered mesoporous metal oxides formation were successfully realized in one-step procedure. Transmission electron microscopy (TEM), energy-dispersive X-ray (EDX), elemental mapping, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were employed to characterize the as-prepared nanocomposites. The hybrid architecture enables a good combination of electrochemically active metal oxide nanoparticles and graphene sheets, leading to the electrocatalytic advantages of both nitrogen doped graphene and ordered mesoporous metal oxides. The electrocatalytic performance of the nanocomposites was studied by using glucose, L-cysteine, uric acid (UA) and H2O2 as redox probes. The performance of OMM (M: Co, Fe)-NGR is found to be greatly improved compared to NGR. Furthermore, electrocatalytic quantitative and qualitative detection performance of OMM (M: Co, Fe)-NGR have been studied in detail. OMM (M: Co, Fe)-NGR exhibits outstanding electrocatalytic activity towards the probes with low detection limits, high reproducibility, good selectivity and long stability. The present OMM (M: Co, Fe)-NGR is a promising nanomaterial for electrochemical biosensing application.

Facile synthesis of Au-embedded porous carbon from metal-organic frameworks and for sensitive detection of acetaminophen in pharmaceutical products

Here we report an Au nanoparticles supported on nanostructured porous carbon (NPCs) hybrid through a coordination-assisted strategy. Metal-organic frameworks (MOFs) have been demonstrated as suitable precursors for preparing NPCs through the impregnation of a secondary carbon source within pores of MOFs. The thermal transformation of Au/UiO-66-NH2 composites in an inert atmosphere has yielded ultrafine Au-embedded NPCs (Au/NPCs). The formation of these composite materials was verified by a comprehensive characterization using X-ray diffraction, N2 adsorption, scanning electron microscopy, and transmission electron microscopy. Because of the unique structural properties and synergetic catalytic effect, Au/NPCs can be developed as an effective sensing platform for the detection of acetaminophen (AP), which showed high activity and excellent analytical performance towards AP, such as a wide linear range of 0.12-95.10u202fμM, a high sensitivity of 357.62u202fμAu202fmM-1, and a low limit of detection of 49.4u202fnM. Importantly, the successfully fabricated Au/NPCs device accurately measured the amount of AP in pharmaceutical samples.

Facile synthesis of platinum-embedded zirconia/porous carbons tri-component nanohybrids from metal-organic framework and their application for ultra-sensitively detection of methyl parathion

Pt nanoparticles immobilized on zirconium oxide (ZrO2) and porous carbons (Pt/ZrO2/PCs) tri-component nanohybrids derived from Pt/ metal-organic frameworks (MOFs) were synthesized. They were prepared by using Pt/MOFs as a template. Additionally, MOFs (UiO-66, a traditional MOFs) were used as ZrO2 and carbon sources without the need of additional precursors. The formation of these composite materials was confirmed through a comprehensive characterization such as transmission electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. The Pt/ZrO2/PCs show strong affinity toward the phosphate group and highly electrocatalytic activity for nitro compound on methyl parathion (MP) molecules. The high performance is owing to the combination of unique electrocatalytic activity of Pt species, excellent conductivity of PCs, and good adsorption properties of ZrO2 crystals for MP. The proposed Pt/ZrO2/PCs tri-component nanocomposite sensor realized the ultrasensitive detection of MP with a wide linear range between 3.8u202f×u202f10-9 and 1.14u202f×u202f10-2u202fmM and a low limit of detection of 1.45u202f×u202f10-9u202fmM. Therefore, it can be developed as an effective sensing platform for the detection of MP.

A label-free electrochemical biosensor for ultra-sensitively detecting telomerase activity based on the enhanced catalytic currents of acetaminophen catalyzed by Au nanorods

An electrochemical biosensor was designed for the determination of telomerase activity using an enzyme-free, PCR-free, and convenient electrochemical strategy. In this work, the electrochemical biosensor was constructed through the functionalization of Au nanorods with a carboxylic group (AuNRs-3) and subsequent immobilization with capture DNA (cDNA) for sensing telomerase activity. Upon telomerase triggered extension, the telomerase activity is related to the amount of the adsorbed electrocatalyst, leading to the different electrochemical signals for readout. Integrating with the efficient electrocatalysis of AuNRs-3-cDNA towards oxidation of acetaminophen, the prepared biosensor exhibits a wide dynamic correlation of telomerase activity from 1u202f×u202f102 to 1.04u202f×u202f107 HeLa cells mL-1 with a sensitivity of 2.68 HeLa cell mL-1 and the limit of detection was calculated to be 52.81 HeLa cells mL-1 under the optimal experimental conditions. Furthermore, the application of this electrochemical biosensor would provide the great potential for analysis of telomerase activity, revealing a powerful platform for early diagnosis of cancers.