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In this work, the low-cost carbon nanorods assembled hierarchical meso-macroporous carbons networks aerogels (CNs-HMCNAs) was environment-friendly synthesized from a cheap and abundant biomass of apples (Malus pumila Mill) for the first time. The biomass of apples derived CNs-HMCNAs exhibited the unique hierarchical meso-macroporous structure with large specific surface area and high density of edge defective sites. At the CNs-HMCNAs modified GCE (CNs-HMCNAs/GCE), the electron transfer between the glassy carbon electrode (GCE) and the ascorbic acid (AA) (or hydrogen peroxide (H 2 O 2 )) was effectively enhanced, and thus induced a low overvoltage for AA electrooxidation (or H 2 O 2 electroreduction). As an electrochemical AA (or H 2 O 2 ) sensor, the CNs-HMCNAs/GCE exhibited wider linear range, lower detection limit, higher sensitivity and stability than GCE and the carbon nanotubes modified GCE (CNTs/GCE). In particular, the CNs-HMCNAs/GCE showed great potential feasibility in the practical determination of AA (in AA injection, Vitamin C tablet and kiwi juice) or H 2 O 2 (in human urine, milk and beer)., (Copyright © 2018 Elsevier B.V. All rights reserved.)

In this work, a novel enzyme-free glucose and hydrogen peroxide (H 2 O 2 ) sensor based on Ni 3 N nanoparticles on conductive 3D graphene aerogels (Ni 3 N/GA) has been successfully synthesized by using hydrothermal reaction, freeze-dried and then calcined under NH 3 atmosphere. The obtained Ni 3 N/GA composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), nitrogen adsorption-desorption isotherms and electrochemical methods. The results show the obtained 3D Ni 3 N/GA composites exhibit excellent electrochemical performance toward glucose oxidation and H 2 O 2 reduction with larger catalytic rate constant K cat value of 3.75 × 10 3  M -1  s -1 and 1.24 × 10 3  M -1  s -1 , respectively. As a glucose sensor, the obtained electrode provides a wide detection range of 0.1-7645.3 μM, fast response time within 3 s, high sensitivity of 905.6 μA mM -1  cm -2 and low detection limit of 0.04 μM. For detection of H 2 O 2 , this prepared sensor offers a wide detection range (5 μM-75.13 mM), fast response time (within 5 s), sensitivity (101.9 μA mM -1  cm -2 ) and low detection limit (1.80 μM). This enzyme-free glucose and H 2 O 2 sensor display satisfactory selectivity, reproducibility and long-term storage stability. Additionally, the sensor can also be used for glucose and H 2 O 2 detection in human blood serum. The results demonstrate that 3D GA nanostructures provide an enviable conductive network for efficient charge transfer and avoid Ni 3 N nanoparticles aggregation, which is advantageous for electrocatalytic applications., (Copyright © 2018 Elsevier B.V. All rights reserved.)

In this study, we developed a novel biosensor based on highly exposed Pt nanoparticles (Pt NPs) decorated porous graphene (PG) for the reliable detection of extracellular hydrogen peroxide (H2O2) released from living cells. The commercially available low-cost hydrophilic CaCO3 spheres were used as template for preparing PG. The porous structure provided larger surface area and more active sites. Due to the porous structure of PG, the Pt NPs supported on PG were not secluded by aggregated graphene layers and were highly exposed to target molecules. Ultrafine Pt NPs were well dispersed and loaded on PG by a method of microwave assistance. Electrochemical performances of the Pt/PG nanocomposites modified glassy carbon electrode (GCE) were investigated. The electrocatalytic reduction of H2O2 showed a wide linear range from 1 to 1477 μM, with a high sensitivity of 341.14 μA mM(-1) cm(-2) and a limit of detection (LOD) as low as 0.50 μM. Moreover, the Pt/PG/GCE exhibited excellent anti-interference property, reproducibility and long-term storage stability. Because of these remarkable analytical advantages, the constructed sensor was used to determine H2O2 released from living cells with satisfactory results. The superior catalytic activity makes Pt/PG nanocomposites a promising candidate for electrochemical sensors and biosensors design., (Copyright © 2015 Elsevier B.V. All rights reserved.)

The one-pot synthesis of a well-defined Au nanoparticles@polyoxometalates/ordered mesoporous carbon (Au@POMs/OMC) tri-component nanocomposite is reported, which is facile, green and rapid. The polyoxometalates were used as both reductant and bridging molecules. The formation of these composite materials was verified by a comprehensive characterization using X-ray diffraction, X-ray photoelectron spectroscopy, energy-dispersive X-ray spectra, scanning electron microscopy, and transmission electron microscopy. The novel nanohybrids of Au@POMs/OMC can provide new features of electrocatalytic activities, because of the synergetic effects of Au nanoparticles and OMC materials. Most importantly, the amperometric measurements show that the Au@POMs/OMC nanohybrids have a high catalytic activity with a good sensitivity, long-term stability, wide linear range, low detection limit, and fast response towards acetaminophenol, H2O2, and NADH detection for application as an enzyme-free biosensor., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Two-dimensional ordered mesoporous carbon nitride (OMCN) has been successfully prepared for the first time using SBA-15 mesoporous silica and melamine as template and precursor respectively, by a nano hard-templating approach. A series of OMCN-x samples with different pyrolysis temperatures have been reported. The formation of these composite materials was verified by detailed characterization (e.g., Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, N2 adsorption, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy). The results showed that the materials were structurally well ordered with two-dimensional porous structure, high surface area and large pore volume. The influence of BET surface area and different amounts of N-bonding configurations formed at different pyrolysis temperatures of OMCN-x for the electrocatalysis towards hydrogen peroxide, nitrobenzene, and nicotinamide adenine dinucleotide were investigated in detail. Results indicated that OMCN treated at 800°C with largest BET surface area and highest amounts of pyrindinic N showed improved electrocatalytic activity for H2O2, nitrobenzene, and NADH in neutral solution., (© 2013 Published by Elsevier B.V.)

Polydopamine (PDA)-coated ordered mesoporous carbons (OMCs) are easily prepared through one-step self-polymerization of dopamine on OMCs matrix at room temperature. Pt nanoparticles (NPs) are deposited on OMCs-PDA via a simple chemical reduction. The PDA layer helps to improve the water-solubility and dispersibility of OMCs, and plays a key role in the deposition of uniform and well-distributed Pt NPs. Transmission electron microscopy images reveal that the ultra-fine Pt NPs with an average size of ~1.8 nm are well-dispersed on the surface of OMCs-PDA. The electrocatalytic behavior of OMCs-PDA/Pt modified glassy carbon (GC) electrode is investigated by cyclic voltammetry and current-time methods using hydrogen peroxide (H2O2) and hydrazine (N2H4) as redox probes. Results show that OMCs-PDA/Pt exhibits improved electrocatalytic activity towards H2O2 reduction and N2H4 oxidation compared with OMCs/Pt. The linear electro-redox responses are found for H2O2 and N2H4 in the range of 2-14324 μM and 1-229 μM with the detection limit (S/N=3) of 0.85 μM and 0.51 μM, respectively. In addition, this new nanocomposite modified electrode exhibits high sensitivity, good anti-interference ability, excellent reproducibility and long-term stability., (Copyright © 2013 Elsevier B.V. All rights reserved.)

The Cu-based MOF loaded on macroporous carbon (MPC) creates novel Cu-MOF-MPC hybrids for the first time. The obtained Cu-MOF-MPC composites are used as electrocatalysts for the oxidation of NADH and reduction of H2O2 in neutral solution.

Poly(ionic liquid) (PIL) coated ordered mesoporous carbons (OMCs) were prepared by in situ polymerization of 3-ethyl-1-vinylimidazolium tetrafluoroborate ([VEIM]BF(4)) monomer on OMCs matrix. PIL on the surface of OMCs can provide sufficient binding sites to anchor the precursors of metal ion. PIL/OMCs were employed as support material for the deposition and formation of ultra-fine Pt nanoparticles, via the self-assembly between the negative Pt precursor and positively charged functional groups of PIL-functionalized OMCs. The combination of the unique properties of each component endows Pt/PIL/OMCs as a good electrode material. Compared with the Pt/OMCs nanocomposite, the Pt/PIL/OMCs modified electrode displays high electrocatalytic activity towards hydrogen peroxide (H(2)O(2)) and gives linear range from 1.0 × 10(-7) to 3.2 × 10(-3) M (R=0.999). The Pt/PIL/OMCs responds very rapidly to the changes in the level of H(2)O(2), producing steady-state signals within 4-5s. A high sensitivity of 24.43 μA mM(-1) and low detection limit of 0.08 μM was obtained at Pt/PIL/OMCs modified electrode towards the reduction of H(2)O(2). The improved activity makes Pt/PIL/OMCs nanocomposite promising for being developed as an attractive robust and new electrode material for electrochemical sensors and biosensors design., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Onion-like mesoporous carbon vesicle (MCV) with multilayer lamellar structure was synthesized by a simply aqueous emulsion co-assembly approach. Palladium (Pd) nanoparticles were deposited on the MCV matrix (Pd/MCV) by chemical reduction of H(2)PdCl(4) with NaBH(4) in aqueous media. Pd(X)/MCV (X wt.% indicates the Pd loading amount) nanocomposites with different Pd loading amount were obtained by adjusting the ratio of precursors. The particular structure of the MCV results in efficient mass transport and the onion-like layers of MCV allows for the obtainment of highly dispersed Pd nanoparticles. The introduction of Pd nanoparticles on the MCV matrix facilitates hydrazine oxidation at more negative potential and delivers higher oxidation current in comparison with MCV. A linear range from 2.0 x 10(-8) to 7.1 x 10(-5) M and a low detection limit of 14.9 nM for hydrazine are obtained at Pd(25)/MCV nanocomposite modified glassy carbon (GC) electrode. A nonenzymatic amperometric sensor for hydrogen peroxide based on the Pd(25)/MCV nanocomposite modified GC electrode is also developed. Compared with MCV modified GC electrode, the Pd(25)/MCV nanocomposite modified GC electrode displays enhanced amperometric responses towards hydrogen peroxide and gives a linear range from 1.0 x 10(-7) to 6.1 x 10(-3) M. The Pd(25)/MCV nanocomposite modified GC electrode achieves 95% of the steady-current for hydrogen peroxide within 1s. The combination of the unique properties of Pd nanoparticles and the porous mesostructure of MCV matrix guarantees the improved analytical performance for hydrazine and hydrogen peroxide., (Copyright 2010 Elsevier B.V. All rights reserved.)

A simple and facile synthetic method to incorporate Pt nanoparticles inside the mesopores of ordered mesoporous carbons (OMCs) is reported. The Pt/OMCs nanocomposite was characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and nitrogen adsorption-desorption. The results show that the incorporation of Pt nanoparticles inside the pores of OMCs does not change the highly ordered two-dimensional hexagonal mesostructure of OMCs matrix. Nonenzymatic amperometric sensor of hydrogen peroxide and glucose based on the Pt/OMCs nanocomposite-modified glassy carbon (GC) electrode is developed. Compared with the original OMCs-modified electrode, the Pt/OMCs-modified electrode displays improved current response towards hydrogen peroxide and gives linear range from 2 to 4212 microM. At an applied potential of -0.08 V, the Pt/OMCs nanocomposite gives linearity in the range of 0.5-4.5 mM glucose in neutral buffered saline solution. This glucose sensor also exhibits good ability of anti-interference to electroactive molecules. The combination the unique properties of Pt nanoparticles and the ordered mesostructure of OMCs matrix guarantees the enhanced response for hydrogen peroxide and glucose., (Copyright 2010 Elsevier B.V. All rights reserved.)

A simple and facile synthetic method to incorporate copper sulfide (Cu(2)S) nanoparticles inside the mesopores of ordered mesoporous carbons (OMCs) is reported. The Cu(2)S/OMCs nanocomposite was characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and nitrogen adsorption-desorption. The results show that the incorporation of Cu(2)S nanoparticles inside the pores of OMCs does not change the highly ordered two-dimensional hexagonal mesostructure of OMCs matrix. Nonenzymatic amperometric sensor of hydrogen peroxide based on the Cu(2)S/OMCs nanocomposite modified glassy carbon (GC) electrode is developed. Compared with the pristine OMCs modified electrode, the Cu(2)S/OMCs modified electrode displays high electrocatalytic activity towards hydrogen peroxide and gives linear range from 1 to 3030 microM (R=0.9986). The sensor also exhibits good ability of anti-interference to electroactive molecules. The combination of the unique properties of Cu(2)S nanoparticles and the ordered mesostructure of OMCs matrix guarantee the excellent electrocatalysis for hydrogen peroxide. The good analytical performance and low-cost make Cu(2)S/OMC nanocomposite promising for the development of effective sensor for hydrogen peroxide., ((c) 2009 Elsevier B.V. All rights reserved.)

A novel porphyrinic iron metal-organic framework (pFeMOF)-decorated ordered mesoporous carbon (OMC) was developed to detect hydrogen peroxide (H 2 O 2 ) released from viable cells. The pFeMOF/OMC hybrid materials were synthesized via a simple one-step hydrothermal method. Fe (III) ion could coordinate with carboxylates of porphyrin groups strongly, leading to more stable MOFs. Because of the mimic peroxidase property of pFeMOF, amplified electrochemical signal could be obtained. The carbon skeleton of OMC revealed a function of restriction for the growth of pFeMOF crystallites, resulting in more active sites to reduce H 2 O 2 . The increased amount of mesopores brings faster diffusion. Moreover, the electrical conductivity and stability has been improved due to the introduction of OMC. The electrocatalytic reduction of H 2 O 2 displayed two segments linearity range from 0.5 to 70.5 μM and 70.5 to 1830.5 μM, with high sensitivity of 67.54 μA mM −1 in the range of low concentration and 22.29 μA mM −1 of high concentration as well as a low limit of detection (LOD) as 0.45 μM. In addition, the pFeMOF/OMC/glassy carbon electrode (GCE) exhibited outstanding property to resist interference, long-term stability and repeatability. Due to these excellent analytical performances, the as-prepared biosensor was applied to detect H 2 O 2 released from living cells with satisfactory outcome. These results display that this new nanocomposite has the potential to fabricate electrochemical sensing platform for nonenzymatic biosensing. [ABSTRACT FROM AUTHOR]

In this work, Pd nanoparticles/porous graphene (Pd/PGR) is prepared by simultaneous reduction of graphene oxide (GO) and Pd precursor in sodium borohydride (NaBH 4 ) solutions at the electrode surface. In this preparation, the positively charged ZnO with high isoelectric point is used as templates for the adsorption of negatively charged GO in water. Then, the poly(diallyldimethylammonium chloride) (PDDA) is added into the ZnO/GO through the electrostatic interaction between the negative charge of GO and positive charge of PDDA. Subsequently, PDDA/ZnO/GO is employed as a support material for the adsorption of chloropalladic acid ions (PdCl 4 2 − ), via the self-assembly between the negative Pd precursor and positively charged functional groups of PDDA. One-step reduction of Pd precursor/PDDA/ZnO/GO in NaBH 4 solutions and the subsequent removal of the ZnO produce Pd/PDDA/PGR with a porous structure at the electrode surface. With a porous morphology and large surface area for both efficient exposure of Pd nanoparticles and enhanced electrolyte-reactant diffusion, a sensitive enzymeless sensor of hydrogen peroxide (H 2 O 2 ) is constructed. Compared with the nonporous Pd/PDDA/GR, the Pd/PDDA/PGR displays high electrocatalytic activity towards H 2 O 2 , exhibiting a high sensitivity of 57.7 μA mM − 1 and low detection limit of 0.9 μM towards the reduction of H 2 O 2 . The improved activity and simple preparation method makes Pd/PDDA/PGR promising for being developed as an attractive robust and new electrode material for electrochemical sensor and biosensor fabrication. [ABSTRACT FROM AUTHOR]

Abstract: Two-dimensional ordered mesoporous carbon nitride (OMCN) has been successfully prepared for the first time using SBA-15 mesoporous silica and melamine as template and precursor respectively, by a nano hard-templating approach. A series of OMCN-x samples with different pyrolysis temperatures have been reported. The formation of these composite materials was verified by detailed characterization (e.g., Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, N2 adsorption, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy). The results showed that the materials were structurally well ordered with two-dimensional porous structure, high surface area and large pore volume. The influence of BET surface area and different amounts of N-bonding configurations formed at different pyrolysis temperatures of OMCN-x for the electrocatalysis towards hydrogen peroxide, nitrobenzene, and nicotinamide adenine dinucleotide were investigated in detail. Results indicated that OMCN treated at 800°C with largest BET surface area and highest amounts of pyrindinic N showed improved electrocatalytic activity for H2O2, nitrobenzene, and NADH in neutral solution. [Copyright &y& Elsevier]

A simple method was developed to prepare a cobalt(II) Schiff base (Co(salen))/large mesoporous carbon (LMC) composite film. The structure and electrocatalytic performance of the Co(salen)/LMC film were investigated by scanning electron microscopy (SEM) and cyclic voltammetry (CV). The Co(salen)/LMC film exhibits high electrocatalytic activity toward H2O2, such as low detection limit (8.5×10−7 M) and wide linear concentration range (2.0×10−6-8.9×10−3 M). Furthermore, glucose oxidase (GOD) was self-assembled on the surface of the Co(salen)/LMC film modified electrode. Determination of glucose in human blood serum with satisfying result was investigated by the resulting biosensor. [ABSTRACT FROM AUTHOR]

Abstract: In this work, platinum–palladium alloy nanoparticles/large mesoporous carbon nanocomposites (Pt x Pd y /LMC) (X:Y indicates the different Pt, Pd atomic ratios) are prepared. Transmission electron microscopy, nitrogen adsorption–desorption, X-ray photoelectron spectra and X-ray diffraction were used to characterize the morphology and structure of LMC or its nanocomposites. Hydrogen peroxide and nitrite were employed as the probes to measure the electrochemical applications of Pt x Pd y /LMC. The introduction of Pt x Pd y alloy nanoparticles on LMC matrix facilitates hydrogen peroxide reduction and nitrite oxidation compared to Pt deposited on LMC matrix (Pt/LMC) and LMC. Amperometry was selected to evaluate the electrocatalytic activity of the Pt1Pd1/LMC nanocomposite modified glassy carbon electrode (Pt1Pd1/LMC/GCE). Results indicate that the Pt1Pd1/LMC/GCE shows higher electrocatalytic performance (wider linear range, lower detection limit and higher sensitivity) for hydrogen peroxide reduction and nitrite oxidation than many sensors reported before. The easy fabrication and excellent electrocatalytic capability of the Pt1Pd1/LMC/GCE can be expected to find practical applications to detect other compounds. [Copyright &y& Elsevier]

Abstract: A novel material based on cupric(II) oxide/macroporous carbon nanocomposites (CuO/MPC) has been prepared through a simple hydrothermal process. In the process of synthesis, the incorporation of MPC leads to a well-dispersed CuO nanoneedles on the surface of MPC. The new composite material combined the unique property of CuO and MPC, showed improved electrochemical activity towards H2O2 reduction and glucose oxidation. Based on the improved electrochemical property of CuO/MPC modified electrode, it can be used as sensor for the determination of H2O2 and glucose. In addition, the CuO/MPC modified electrode displayed good stability and antifouling features towards glucose oxidation. These results also indicate that CuO/MPC nanocomposites have of wide application foreground. [Copyright &y& Elsevier]

In this work, a new enzymeless sensor for hydrogen peroxide (H 2 O 2 ) was constructed by supporting CoFe nanoparticles on the nitrogen-doped graphene (CoFe/NGR). In this preparation, the graphene oxide (GO) is first used as substrate for the growth of CoFe layered double hydroxides (CoFe LDHs) through hydrothermal reaction. Then, the pyrolysis of CoFe LDHs/GO under NH 3 produces CoFe/NGR. By supporting CoFe nanoparticles on NGR support, the electrocatalytic performance of CoFe is dramatically improved because of high electric conductivity of NGR. Consequently, the combination of CoFe and NGR allows the nonenzymatic detection of H 2 O 2 . Compared with the unsupported CoFe nanoparticles, the CoFe/NGR displays high electrocatalytic activity towards H 2 O 2 , enabling a high sensitivity of 435.7 μA mM −1 cm −2 and low detection limit of 0.28 μM towards the reduction of H 2 O 2 . Especially, the attractive feature of low cost and outstanding analytical performance of CoFe/NGR suggest it great potential in electrochemical sensor and biosensor fabrication. [ABSTRACT FROM AUTHOR]

In this work, a novel porphyrinic metal-organic framework-based composite has been successfully synthesized by a simple one-step solvothermal method through growing Zr-PorMOF on macroporous carbon (MPC). Porphyrin-base MOFs combining the structural adjustable of MOFs and the specific catalytic activity of biomimetic catalysts play an important role in electrocatalysis. A series of characterization show that the roles of MPC as follow: (1) MPC could avoid the agglomeration of Zr-PorMOF particles and increase the specific surface area; (2) MPC could improve the electrochemical stability of Zr-PorMOF particles; (3) MPC could reduce the electron transfer resistance. Therefore, MPC plays the role of the conductive bridges to provide facile charge transport. The obtained Zr-PorMOF/MPC composites exhibit much better electrocatalytic activity for the reduction of hydrogen peroxide (H 2 O 2 ) than the pristine Zr-PorMOF due to the synergy of Zr-PorMOF and MPC. This enzyme-free H 2 O 2 sensor shows two linear relationships in the ranges 0.5–137 μM (R 2 = 0.991, sensitivity = 66 μA mM −1 ) and 137–3587 μM (R 2 = 0.993, sensitivity = 16 μA mM −1 ), with a low over-potential at −0.2 V, a fast response time within 1 s and a low limit of detection (LOD) of 0.18 μM. Moreover, Zr-PorMOF/MPC composites were used to simultaneously detect uric acid (UA), xanthine (XA) and hypoxanthine (HX). These three substances are degradation products of purine metabolism. In addition, Zr-PorMOF/MPC composites can be used to develop multifunctional biosensors. [ABSTRACT FROM AUTHOR]

In the present work, we described a green and facile fabrication of mixed manganese-iron oxide loaded carbon fibers (Mn 2 O 3 -Fe 2 O 3 /CFs) through electrospinning and subsequent heat treatment processes. For optimal performance, a series of samples were synthesized by the same way with varying Mn/Fe molar ratios (1:0, 3:1, 1:1, 1:3, 0:1) in precursors. The composition, morphology and catalytic property of as-prepared samples were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray powder diffraction (XRD), X-ray photo-electron spectroscopy (XPS) and electrochemical methods. Mn 2 O 3 -Fe 2 O 3 /CFs (3:1) exhibits the highest catalytic ability towards hydrogen peroxide (H 2 O 2 ) reduction and hydrazine (N 2 H 4 ) oxidation. Furthermore, Mn 2 O 3 -Fe 2 O 3 /CFs/GCE (3:1) displays remarkable analytical performances for the detection of H 2 O 2 and N 2 H 4 in terms of wide linear range, low limit of detection, short current response time, excellent anti-interference ability, good repeatability and long-time stability. In addition, it can be applied to the analysis of real samples with satisfactory results. [ABSTRACT FROM AUTHOR]

Abstract: This article reports on the electrochemical property of large mesoporous carbons (LMC) synthesized using nano-CaCO3 as a template and sucrose as a carbon precursor. Though a simple preparation method for LMC, the LMC modified glassy carbon electrode (LMC/GCE) exhibited good electrochemical activity for some common electroactive compounds, such as ascorbic acid (AA), uric acid (UA), epinephrine (EP) and tryptophan (Trp). The unique properties of LMC were also compared with those of carbon nanotubes (CNT), and the results showed that the LMC possessed a much better property than CNT. In addition, the LMC/GCE was also used to analyze the β-nicotinamide adenine dinucleotide (NADH) and hydrogen peroxide (H2O2) and showed a high sensitivity and low detection limit. Based on a simple preparation method and good electrochemical property, the LMC represents a new class of carbon electrode for electrochemical sensor applications. [ABSTRACT FROM AUTHOR]

In this paper, kelp ( Laminaria japonica ), as a kind of abundant biomass, is used as the precursor for the preparation of kelp-derived hierarchical meso-macroporous carbons (K-dHMMCs) through the carbonization under nitrogen (N 2 ) atmosphere at high temperature. The K-dHMMCs exhibits the unique structure with high specific surface area of 416.02 m 2  g −1 , large pore volume of 0.24 cm 3  g −1 , the hierarchical meso-macroporous size distribution centered at 2, 12 and 82 nm and high density of defective sites, enabling K-dHMMCs attractive for the electrocatalysis. Drop-casting K-dHMMCs on the glassy carbon (GC) surface allows the construction of K-dHMMCs based electrochemical sensing platform, which shows electrocatalytic activities towards many electroactive molecules, such as potassium ferricyanide, nicotinamide adenine dinucleotide (NADH), hydrogen peroxide (H 2 O 2 ), dopamine (DA), uric acid (UA), ascorbic acid (AA), epinephrine (EP), l -tyrosine (Tyr) and acetaminophen (APAP). Especially, the K-dHMMCs modified GC (K-dHMMCs/GC) electrode exhibits higher sensitivity, wider linear range, and lower detection limit than both carbon nanotubes modified GC (CNTs/GC) and GC electrodes for H 2 O 2 detection, which makes the K-dHMMCs/GC electrode to be able to determine the H 2 O 2 levels in human urine sample and monitor the H 2 O 2 released from human cancer cells. These results demonstrate that K-dHMMCs/GC possesses a great potential for conventional electrochemical sensing applications. [ABSTRACT FROM AUTHOR]

Designing low-cost, high-efficiency and non-noble metal-based electrocatalysts is fairly essential for the commercial utilization of electrochemical sensors and energy conversion devices. Low-cost CuFe 2 O 4 spinel has been widely researched as an electrocatalyst in electrochemical sensors and catalysis. Nevertheless, the low utilization of active sites in bulk CuFe 2 O 4 and the poor electro conductivity of CuFe 2 O 4 invariably restrict its upgrade in catalytic efficiency. Herein, by utilizing the facile electrospinning technique and without involving any template or surfactant, we successfully design three-dimensional (3D) hierarchically porous architecture woven by abundant ultrafine CuFe 2 O 4 crystal-coupled porous carbon nanowires (denoted as CuFe 2 O 4 /PCFs). Characterization results verify the 3D net-like textural structures of CuFe 2 O 4 /PCFs. Especially, the hierarchically porous structure, high surface area, and abundant carbon edges boost the uniform dispersion of tiny CuFe 2 O 4 crystals; these obviously promote the amounts of electrochemically available CuFe 2 O 4 active sites while decreasing the mass transport resistance of CuFe 2 O 4 /PCFs in electrocatalytic processes. Meanwhile, introducing carbon matrices can drastically enhance the electrical conductivity of CuFe 2 O 4 /PCF nanowires. All these advances in structural and physical performances truly make tremendous progress for CuFe 2 O 4 /PCFs for H 2 O 2 reduction and oxygen evolution reaction (OER) catalysis compared with bulk CuFe 2 O 4. For instance, the CuFe 2 O 4 /PCF catalyst exhibits a high sensitivity of 69.18 μA mM−1 cm−2, low detection limit of 1.20 μM and wide linear range of 0.11–22.0 mM for H 2 O 2 sensing. Meanwhile, the CuFe 2 O 4 /PCF catalyst just needs a potential value of 1.589 V (vs. reversible hydrogen electrode) to achieve the OER catalysis current density of 10 mA cm−2 in 1.0 M KOH, it only shows a small Tafel slope of 89.34 mV dec−1 for the OER as well. Our catalyst design strategy of CuFe 2 O 4 /PCF nanowires not only demonstrates the successful design of a novel high-efficiency non-noble-metal catalyst for both OER and H 2 O 2 reduction catalysis but also affords a new methodology for boosting the electrocatalytic abilities of spinel-type hybrid materials by designing a 3D structure and improving conductivity. Image 1 • Ultrafine CuFe 2 O 4 nanocrystallines coupled porous carbon nanowires. • The 3D hierarchical porous net-like architecture consist of CuFe 2 O 4 /PCFs nanowires. • Riched catalytic active sites and excellent electroconductibility for electrocatalysis. • Wide linear range (0.11–22.0 mM) and high sensitivity (69.18 μA mM−1 cm−2) toward H 2 O 2 sensing. • A negative OER E 10 value of 1.589 V vs. RHE and a low Tafel slope of 89.34 mV dec−1. [ABSTRACT FROM AUTHOR]