One step laser-induced synthesis of a bimetallic iron-cobalt sulfide for efficient solar light driven, Fenton-like and electrochemical catalysis.

Pulsed laser irradiation of an equimolar mixture of FeS and CoS onto a Ta substrate results in the one-step formation of bimetallic iron cobalt sulfide. The use of complementary analytical techniques, such as scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, high-resolution electron microscopy, and electron diffraction, confirmed the presence of nanocrystalline cobaltpentlandite [FeCoS] and maghemite [γ-FeO]. The mechanism by which this occurs involves the reactive interaction of laser-ionized Fe, Co, and S species, which subsequently undergo rapid non-equilibrium cooling and deposition.

Expression of concern: An impedimetric immunosensor based on diamond nanowires decorated with nickel nanoparticles.

Expression of concern for 'An impedimetric immunosensor based on diamond nanowires decorated with nickel nanoparticles' by Palaniappan Subramanian , , 2014, , 1726-1731, https://doi.org/10.1039/C3AN02045B.

Expression of concern: Diamond nanowires modified with poly[3-(pyrrolyl)carboxylic acid] for the immobilization of histidine-tagged peptides.

Expression of concern for 'Diamond nanowires modified with poly[3-(pyrrolyl)carboxylic acid] for the immobilization of histidine-tagged peptides' by Palaniappan Subramanian , , 2014, , 4343-4349, https://doi.org/10.1039/C4AN00146J.

Rational construction of porous cobalt nanoparticle integrated nitrogen doped hollow carbon nanostructures for peptide agonist exendin-4 biosensing.

In this study, we designed a point-of-care (POC) testing electrochemical biosensor using an integrated biosensing assay based on hollow-like nitrogen-doped carbon nanostructures combined with cobalt nanoparticles (Co@HNCNs, CoO@HNCNs, and CoP@HNCNs). These are functionalized with Anti-Exendin-4 Antibodies (Anti-Ex-4-Abs) and Bovine Serum Albumin (BSA) to create sensitive probes (Co@HNCNs/Anti-Ex-4-Abs/BSA, CoO@HNCNs/Anti-Ex-4-Abs/BSA, and CoP@HNCNs/Anti-Ex-4-Abs/BSA) for the ultrasensitive detection of exendin-4 (Ex-4), a peptide agonist used in the treatment of type 2 diabetes mellitus (T2DM). Among the cobalt-based carbon nanostructures, the CoO@HNCNs/Anti-Ex-4-Abs/BSA nanoprobe demonstrated superior ability to specifically recognize Ex-4.

Correction: Diamond nanowires modified with poly[3-(pyrrolyl)carboxylic acid] for the immobilization of histidine-tagged peptides.

Correction for 'Diamond nanowires modified with poly[3-(pyrrolyl)carboxylic acid] for the immobilization of histidine-tagged peptides' by Palaniappan Subramanian , , 2014, , 4343-4349, https://doi.org/10.1039/C4AN00146J.

Chemical-Dealloying-Derived PtPdPb-Based Multimetallic Nanoparticles: Dimethyl Ether Electrocatalysis and Fuel Cell Application.

In this work, we report a novel multimetallic nanoparticle catalyst composed of Pt, Pd, and Pb and its electrochemical activity toward dimethyl ether (DME) oxidation in liquid electrolyte and polymer electrolyte fuel cells. Chemical dealloying of the catalyst with the lowest platinum-group metal (PGM) content, PtPdPb/C, was conducted using HNO to tune the catalyst activity. Comprehensive characterization of the chemical-dealloying-derived catalyst nanoparticles unambiguously showed that the acid treatment removed 50% Pb from the nanoparticles with an insignificant effect on the PGM metals and led to the formation of smaller-sized nanoparticles.

NiP Nanoparticle-Inserted Porous Layered NiO Hetero-Structured Nanosheets as a Durable Catalyst for the Electro-Oxidation of Urea.

The electro-oxidation of urea (EOU) is a remarkable but challenging sustainable technology, which largely needs a reduced electro-chemical potential, that demonstrates the ability to remove a notable harmful material from wastewater and/or transform the excretory product of humans into treasure. In this work, an NiP-nanoparticle-integrated porous nickel oxide (NiO) hetero-structured nanosheet (NiP@NiO/NiF) catalyst was synthesized through in situ acid etching and a gas-phase phosphating process. The as-synthesized NiP@NiO/NiF catalyst sample was then used to enhance the electro-oxidation reaction of urea with a higher urea oxidation response (50 mA cm at 1.

Co Nanoparticle-Encapsulated Nitrogen-Doped Carbon Nanotubes as an Efficient and Robust Catalyst for Electro-Oxidation of Hydrazine.

Structural engineering is an effective methodology for the tailoring of the quantities of active sites in nanostructured materials for fuel cell applications. In the present study, Co nanoparticles were incorporated into the network of 3D nitrogen-doped carbon tubes (Co@NCNTs) that were obtained via the molten-salt synthetic approach at 800 °C. Morphological representation reveals that the Co@NCNTs are encompassed with Co nanoparticles on the surface of the mesoporous walls of the carbon nanotubes, which offers a significant active surface area for electrochemical reactions.

Critical Role of Phosphorus in Hollow Structures Cobalt-Based Phosphides as Bifunctional Catalysts for Water Splitting.

Cobalt phosphides electrocatalysts have great potential for water splitting, but the unclear active sides hinder the further development of cobalt phosphides. Wherein, three different cobalt phosphides with the same hollow structure morphology (CoP-HS, CoP -HS, CoP -HS) based on the same sacrificial template of ZIF-67 are prepared. Surprisingly, these cobalt phosphides exhibit similar OER performances but quite different HER performances.

Reduced graphene oxide-based field effect transistors for the detection of E7 protein of human papillomavirus in saliva.

Several challenging biological sensing concepts have been realized using electrolyte-gated reduced graphene oxide field effect transistors (rGO-FETs). In this work, we demonstrate the interest of rGO-FET for the sensing of human papillomavirus (HPV), one of the most common sexually transmitted viruses and a necessary factor for cervical carcinogenesis. The highly sensitive and selective detection of the HPV-16 E7 protein relies on the attractive semiconducting characteristics of pyrene-modified rGO functionalized with RNA aptamer Sc5-c3.

Nickel-phosphate pompon flowers nanostructured network enables the sensitive detection of microRNA.

An electrochemical immuno-nanogenosensor is developed based on noble-metal-free nickel phosphate nanostructure (NiPNs) as an excellent biocompatible material for miRNA detection in blood serum and urine samples without using indicators for the first time. The pompon flower-like morphology of NiPNs is synthesized, and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction pattern (XRD), fourier transform-infrared spectroscopy (FT-IR), and electrochemical impedance methods. The novel NiPNs nanostructured interface was constructed by coordinate covalent bonding between Ni and phosphate group of probe DNA.

Hierarchical core-shell structured NiS/NiMoO nanowires: a high-performance and reusable electrochemical sensor for glucose detection.

Designing highly active electrode is important for the fabrication of electrochemical sensing platforms, and core-shell nanostructures with large specific surface areas and ease of accessibility are effective probes for the detection of biomolecules. In this work, we report the development of hierarchical core-shell Ni3S2/NiMoO4 nanowires on a nickel foam substrate (Ni-Ni3S2/NiMoO4) as a non-noble metal catalyst electrode for the electrochemical oxidation of glucose in alkaline electrolyte. As an electrochemical sensor for glucose detection, the fabricated hierarchical Ni-Ni3S2/NiMoO4 core-shell nanowires display an enhanced catalytic response, a fast response time of 1 s with a limit of detection (LOD) of 0.

Simultaneous Mapping of Oxygen Reduction Activity and Hydrogen Peroxide Generation on Electrocatalytic Surfaces.

Electrochemical scanning probe microscopies have become valuable experimental tools, owing to their capability of capturing topographic features in addition to mapping the electrochemical activity of nanoscale oxygen reduction catalysts. However, most scanning probe techniques lack the ability to correlate topographic features with the electrochemical oxygen reduction and peroxide formation in real time. In this report, we show that it is indeed possible to construct high-resolution catalytic current maps at an electrified solid-liquid interface by placing a specially made Au-coated SiO Pt atomic force microscopy and scanning electrochemical microscopy (AFM-SECM) dual electrode tip approximately 4-8 nm above the reaction center.

Cobalt Oxide Porous Nanocubes-Based Electrochemical Immunobiosensing of Hepatitis B Virus DNA in Blood Serum and Urine Samples.

In this work, we report a new biosensing platform for hepatitis B virus (HBV) DNA genosensing using cobalt oxide (CoO) nanostructures. The tunable morphologies of CoO nanostructures such as porous nanocubes (PNCs), nanooctahedra (NOHs), and nanosticks (NSKs) are synthesized, and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) patterns, nitrogen adsorption/desorption isotherms (BET), and electrochemical impedance spectral (EIS) methods. The HBV probe DNA (ssDNA) is immobilized on the CoO nanostructures through coordinate bond formation between nucleic acid of ssDNA and Co metal, which results in highly stable nanostructured biosensing platform.

Plasmon-Induced Electrocatalysis with Multi-Component Nanostructures.

Noble metal nanostructures are exceptional light absorbing systems, in which electron⁻hole pairs can be formed and used as "hot" charge carriers for catalytic applications. The main goal of the emerging field of plasmon-induced catalysis is to design a novel way of finely tuning the activity and selectivity of heterogeneous catalysts. The designed strategies for the preparation of plasmonic nanomaterials for catalytic systems are highly crucial to achieve improvement in the performance of targeted catalytic reactions and processes.

Nanoscale mapping of catalytic hotspots on Fe, N-modified HOPG by scanning electrochemical microscopy-atomic force microscopy.

The scanning electrochemical microscopy-atomic force microscopy (SECM-AFM) technique is used to map catalytic currents post Fe and N surface modification of graphitic carbon with an ultra-high resolution of 50 nm. The oxidation current of the partial reduction product, hydrogen peroxide, was also mapped in the same location in the graphitic carbon. The current mapping and ex situ spectroscopic evidence revealed that Fe-coordinated nitrogen sites formed both in the edge and basal planes of highly ordered pyrolytic graphite (HOPG) constitute the primary oxygen reduction catalytic sites in acid solutions of this important yet insufficiently understood class of catalysts.

Exceptionally Active and Stable Spinel Nickel Manganese Oxide Electrocatalysts for Urea Oxidation Reaction.

Spinel nickel manganese oxides, widely used materials in the lithium ion battery high voltage cathode, were studied in urea oxidation catalysis. NiMn2O4, Ni1.5Mn1.

Vertically Aligned Nitrogen-Doped Carbon Nanotube Carpet Electrodes: Highly Sensitive Interfaces for the Analysis of Serum from Patients with Inflammatory Bowel Disease.

The number of patients suffering from inflammatory bowel disease (IBD) is increasing worldwide. The development of noninvasive tests that are rapid, sensitive, specific, and simple would allow preventing patient discomfort, delay in diagnosis, and the follow-up of the status of the disease. Herein, we show the interest of vertically aligned nitrogen-doped carbon nanotube (VA-NCNT) electrodes for the required sensitive electrochemical detection of lysozyme in serum, a protein that is up-regulated in IBD.

Diamond nanowires modified with poly[3-(pyrrolyl)carboxylic acid] for the immobilization of histidine-tagged peptides.

Coating boron-doped diamond nanowires (BDD NWs) with a conducting polymer, poly[3-(pyrrolyl)carboxylic acid], has been reported. Polymer coating was achieved through electropolymerization of 3-(pyrrolyl)carboxylic acid at the electrode interface by amperometrically biasing the BDD NWs interface until a predefined charge has passed. The poly[3-(pyrrolyl)carboxylic acid] modified BDD NWs (PPA-BDD NWs) were characterized by scanning electron microscopy (SEM) and cyclic voltammetry (CV).

An impedimetric immunosensor based on diamond nanowires decorated with nickel nanoparticles.

Nanostructured boron-doped diamond has been investigated as a sensitive impedimetric electrode for the detection of immunoglobulin G (IgG). The immunosensor was constructed in a three-step process: (i) reactive ion etching of flat boron-doped diamond (BDD) interfaces to synthesize BDD nanowires (BDD NWs), (ii) electrochemical deposition of nickel nanoparticles (Ni NPs) on the BDD NWs, and (iii) immobilization of biotin-tagged anti-IgG onto the Ni NPs. Electrochemical impedance spectroscopy (EIS) was used to follow the binding of IgG at different concentrations without the use of any additional label.

Graphene-coated surface plasmon resonance interfaces for studying the interactions between bacteria and surfaces.

A variety of physical and chemical parameters are of importance for adhesion of bacteria to surfaces. In the colonization of mammalian organisms for example, bacterial fimbriae and their adhesins not only seek particular glycan sequences exposed on diverse epithelial linings, they also enable the bacteria to overcome electrostatic repulsion exerted by their selected surfaces. In this work, we present a new technique based on simplified model systems for studying the adhesion strength of different Escherichia coli strains.

Lysozyme detection on aptamer functionalized graphene-coated SPR interfaces.

The paper reports on a surface plasmon resonance (SPR)-based approach for the sensitive and selective detection of lysozyme. The SPR sensor consists of a 50 nm gold film coated with a thin film of reduced graphene oxide (rGO) functionalized with anti-lysozyme DNA aptamer. The SPR chip coating with rGO matrix was achieved through electrophoretic deposition of graphene oxide (GO) at 150 V.

Peroxynitrite activity of hemin-functionalized reduced graphene oxide.

Conducting interfaces modified with reduced graphene oxide (rGO) have shown improved electrochemical response for different analytes. The efficient formation of functionalized rGO based materials is thus of current interest for the development of sensitive and selective biosensors. Herein, we report a simple and environmentally friendly method for the formation of a hemin-functionalized rGO hybrid nanomaterial that exhibits remarkable sensitivity to peroxynitrite (ONOO(-)) in solution.

Localized surface plasmon resonance interfaces coated with poly[3-(pyrrolyl)carboxylic acid] for histidine-tagged peptide sensing.

The paper reports on a novel localized surface plasmon resonance (LSPR) substrate architecture for the immobilization and detection of histidine-tagged peptides. The LSPR interface consists of an ITO (indium tin oxide) substrate coated with gold nanostructures. The latter are obtained by thermal deposition of a thin (2 nm thick) gold film followed by post-annealing at 500 °C.