Mesoporous carbon (MC) materials are important in many areas of technology, such as in storage of hydrogen and methane, supercapacitors, molecular separation, catalysis, etc. In this communication, we demonstrate the proof of concept of using MC microparticles as an effective fluorescent sensing platform for nucleic acid detection with a high selectivity down to single-base mismatch.
In this communication, we demonstrate for the first time the proof of concept that carbon nanoparticles (CNPs) can be used as an effective fluorescent sensing platform for nucleic acid detection with selectivity down to single-base mismatch. The dye-labeled single-stranded DNA (ssDNA) probe is adsorbed onto the surface of the CNP via π-π interaction, quenching the dye. In the target assay, a double-stranded DNA (dsDNA) hybrid forms, recovering dye fluorescence.
In this paper, for the first time, we report on the growth of ultrathin Ni(OH)2 nanosheet arrays on a nickel foam (NF) via a novel pH-driven dissolution–precipitation route, carried out by a hydrothermal treatment of the NF in an acidic medium without the introduction of other nickel sources. Acid etching of the NF surface leads to nano-pits and produces Ni(H2O)n2+ ions at the early stage of the reaction. With the elapsed time, an increase in the pH level occurs and the Ni(H2O)n2+ ions gradually hydrolyze and preferentially precipitate on the nano-pits, serving as nucleation sites and leading to ultrathin Ni(OH)2 nanosheet arrays on an NF. The effects of the experimental parameters, such as reaction time, acid type and starting pH value, on the Ni(OH)2 growth are also investigated. Because the nano-pits are integrated parts of the NF and the deposition of Ni(OH)2 nanosheets on such nano-pits ensures intimate contact between them, the Ni(OH)2/NF is robust enough to withstand a violent sonication process and efficient and rapid electron transfer is achieved. As a binder-free anode for Li-ion batteries, the Ni(OH)2/NF exhibits an unexpected ultrahigh capacity of 1689 mA h g−1 and excellent cycling stability.
Abstract The development of effective and inexpensive hydrogen evolution reaction (HER) electrocatalysts for future renewable energy systems is highly desired. The strongly acidic conditions in proton exchange membranes create a need for acid‐stable HER catalysts. A nanohybrid that consists of carbon nanotubes decorated with CoP nanocrystals (CoP/CNT) was prepared by the low‐temperature phosphidation of a Co 3 O 4 /CNT precursor. As a novel non‐noble‐metal HER catalyst operating in acidic electrolytes, the nanohybrid exhibits an onset overpotential of as low as 40 mV, a Tafel slope of 54 mV dec −1 , an exchange current density of 0.13 mA cm −2 , and a Faradaic efficiency of nearly 100 %. This catalyst maintains its catalytic activity for at least 18 hours and only requires overpotentials of 70 and 122 mV to attain current densities of 2 and 10 mA cm −2 , respectively.
In this article, we report on the use of multi-walled carbon nanotubes (MWCNTs) as an effective fluorescent sensing platform for nucleic acid detection with selectivity down to single-base mismatch. The detection is accomplished with two steps: (1) MWCNTs adsorb and quench the fluorescence of the dye-labeled single-stranded DNA (ssDNA) probe; (2) in the presence of the target, a hybridization event occurs, which produces a double-stranded DNA (dsDNA) that detaches from the MWCNT surface, leading to the restoration of the dye fluorescence. We also compared the sensing responses of MWCNTs and single-walled carbon nanotubes (SWCNTs) under the same experimental conditions.
In this communication, we develop a facile, one-step strategy towards the rapid synthesis of ZnO nanoparticle-decorated reduced graphene oxide (rGO–ZnO) composites by directly immersing Zn plate in a GO solution containing ammonia with the aid of ultrasonication at room temperature. The rGO–ZnO composites obtained have applications in photocurrent generation in the visible spectral region of white light using zinc porphyrin (ZnP) as a photosensitizer.
In this Letter, for the first time, we demonstrated the preparation of a highly efficient electrocatalyst, spinel CuCo2O4 nanoparticles supported on N-doped reduced graphene oxide (CuCo2O4/N-rGO), for an oxygen reduction reaction (ORR) under alkaline media. The hybrid exhibits higher ORR catalytic activity than CuCo2O4 or N-rGO alone, the physical mixture of CuCo2O4 nanoparticles and N-rGO, and Co3O4/N-rGO. Moreover, such a hybrid affords superior durability to the commercial Pt/C catalyst.
An aqueous dispersion of graphene nanosheets (GNs) has been successfully prepared via chemical reduction of graphene oxide (GO) by hydrazine hydrate in the presence of poly[(2-ethyldimethylammonioethyl methacrylate ethyl sulfate)-co-(1-vinylpyrrolidone)] (PQ11), a cationic polyelectrolyte, for the first time. The noncovalent functionalization of GN by PQ11 leads to a GN dispersion that can be very stable for several months without the observation of any floating or precipitated particles. Several analytical techniques including UV−vis spectroscopy, Raman spectroscopy, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) have been used to characterize the resulting GNs. Taking advantages of the fact that PQ11 is a positively charged polymer exhibiting reducing ability, we further demonstrated the subsequent decoration of GN with Ag nanoparticles (AgNPs) by two routes: (1) direct adsorption of preformed, negatively charged AgNPs; (2) in-situ chemical reduction of silver salts. It was found that such Ag/GN nanocomposites exhibit good catalytic activity toward the reduction of hydrogen peroxide (H2O2), leading to an enzymeless sensor with a fast amperometric response time of less than 2 s. The linear detection range is estimated to be from 100 μM to 40 mM (r = 0.996), and the detection limit is estimated to be 28 μM at a signal-to-noise ratio of 3.
In this communication, we demonstrate for the first time that titanium silicalite-1 zeolite microparticles (TSZMs) can effectively catalyze the reduction of H2O2, leading to an enzymeless H2O2 sensor with a linear detection range from 100 μM to 40 mM (r = 0.994) and a detection limit of 0.5 μM at a signal-to-noise ratio of 3.
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