An Efficient Strategy for Boosting Photogenerated Charge Separation by Using Porphyrins as Interfacial Charge Mediators.

Surface recombination at the photoanode/electrolyte junction seriously impedes photoelectrochemical (PEC) performance. Through coating of photoanodes with oxygen evolution catalysts, the photocurrent can be enhanced; however, current systems for water splitting still suffer from high recombination. We describe herein a novel charge transfer system designed with BiVO as a prototype.

Self-Assembly of Biocompatible FeSe Hollow Nanostructures and 2D CuFeSe Nanosheets with One- and Two-Photon Luminescence Properties.

Transition metal chalcogenides are investigated for catalyst, intermediary agency, and particular optical properties because of their distinguished electron-vacancy-transfer (EVT) process toward different applications. In this work, one convenient approach for making pure-phased FeSe nanocrystals (NCs) and doped CuFeSe nanosheets (NSs) through a wet chemistry method in mixed solvents is illustrated. The surface modification of each product is realized by using a peptide molecule glutathione (GSH), in which the thiol group (-SH) is ascribed to be the in situ reducer and bonding agency between the crystalline surface and surfactant in whole constructing processes.

J-Aggregates of zinc tetraphenylporphyrin: a new pathway to excellent electrochemiluminescence emitters.

Low-potential electrochemiluminescence (ECL) luminophores with excellent ECL behavior have attracted considerable interest in biological analysis. Herein, we explored the ECL behavior of ZnTPP with different aggregates for the first time. In this work, we used the mixed solvent method to prepare the H- and J-aggregates of zinc tetraphenylporphyrin (ZnTPP).

Electrochemiluminescence Platforms Based on Small Water-Insoluble Organic Molecules for Ultrasensitive Aqueous-Phase Detection.

Highly efficient detection in the aqueous phase for water-insoluble organic molecule probes is challenging. The bright aggregated-state electrochemiluminescence (ECL) of 1,1-disubstituted 2,3,4,5-tetraphenylsiloles by a co-reactant approach was discovered, and a heterogeneous aggregation-induced emission ECL (HAIE-ECL) was constructed at the electrode surface, showing very high ECL efficiency (37.8 %) and selective recognition for industrially important DNBP plasticizer with a low detection limit of 0.

Ultratrace Naked-Eye Colorimetric Ratio Assay of Chromium(III) Ion in Aqueous Solution via Stimuli-Responsive Morphological Transformation of Silver Nanoflakes.

In this work, we discover an effective domino-effect-based detection mechanism for the rapid, high-selectivity, and ultrasensitive naked-eye colorimetric ratio assay of chromium(III) ion (Cr) in aqueous solutions. This naked-eye colorimetric ratio assay to Cr relies on changes in absorbance properties that are due to the stimuli response of Cr for the morphological transformation of silver nanoflakes. In the presence of Cr, large silver nanoflakes can be stimulated to transform to small nanoparticles (NPs), which promoted a color change in solution from bright yellow to wine red that was detected by the naked eye and spectroscopic absorption methods.

Three-dimensional hierarchical frameworks based on molybdenum disulfide-graphene oxide-supported magnetic nanoparticles for enrichment fluoroquinolone antibiotics in water.

Recently, water pollution caused by antibiotics is rapidly increasing. Thus, developing efficient, fast and sensitive detection methods for environmental antibiotics monitoring are still remaining elusive. Herein, a method for antibiotics analysis including lecofloxacin, pazcofloxacin and gatifloxacin in water by high performance liquid chromatography (HPLC) using molybdenum disulfide-graphene oxide-supported magnetic nanoparticles (FeO/GO/MoS) as the adsorbent of magnetic solid-phase extraction was developed.

Sensitive and selective colorimetric nitrite ion assay using silver nanoparticles easily synthesized and stabilized by AHNDMS and functionalized with PABA.

Nitrite ions (NO ), as one of the important inorganic anions, exhibit considerable effects towards the environment and human health. Moreover, over intake of this anion may cause dangerous diseases. Herein, we successfully fabricated silver nanoparticles (AgNPs) using 4-amino-5-hydroxynaphthalene-2, 7-disulphonic acid monosodium salt (AHNDMS) and functionalized them with -aminobenzoic acid (PABA), and used the functionalised AgNPs as a sensitive and selective colorimetric sensor for nitrite ions.

A simple yet sensitive colorimetric nitrite ions assay based on diazotization with p‑Aminobenzoic and coupling with phloroglucinol in acidic medium.

Immoderate intake of nitrite (NO) is deleterious human health and may result in causing dangerous diseases. In this study, nitrite detection system was successfully fabricated based on a unique diazo-coupling reaction of p‑Aminobenzoic acid (PABA) and phloroglucinol (1, 3, 5‑trihydroxybenzene). Upon the presence of NO in an acid medium, p‑Aminobenzoic acid could not only form diazonium ion easily but also couple with p‑Aminobenzoic acid, and results forming yellow water-soluble azo dye that shows maximum absorption at 434 nm.

Ultrahigh Selective Colorimetric Quantification of Chromium(VI) Ions Based on Gold Amalgam Catalyst Oxidoreductase-like Activity in Water.

Hexavalent chromium ion (Cr) is one of the most toxic substances for plants, for animals, and is a confirmed human respiratory carcinogen. However, so far, there are few independent and efficient colorimetric methods for detection of Cr. Here, we introduce a convenient, label-free, catalysis-based, and efficient strategy for quantification of Cr by using a colorimetric sensing probe 3,3',5,5'-tetramethylbenzidine (TMB).

Three-dimensional porous self-assembled chestnut-like nickel-cobalt oxide structure as an electrochemical sensor for sensitive detection of hydrazine in water samples.

Three-dimensional NiCoO is a kind of superior sensing material owing to its high electron transfer capability, large available surface area and numbers of active sites. In this work, NiCoO of the three-dimensional chestnut-like structure were easily achieved through a one step hydrothermal process. Afterwards, the morphology and structure were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS).

Dual-Emitting Fluorescent Metal-Organic Framework Nanocomposites as a Broad-Range pH Sensor for Fluorescence Imaging.

pH plays an important role in understanding physiological/pathologic processes, and abnormal pH is a symbol of many common diseases such as cancer, stroke, and Alzheimer's disease. In this work, an effective dual-emission fluorescent metal-organic framework nanocomposite probe (denoted as RB-PCN) has been constructed for sensitive and broad-range detection of pH. RB-PCN was prepared by encapsulating the DBI-PEG-NH-functionalized FeO into Zr-MOFs and then further reacting it with rhodamine B isothiocyanates (RBITC).

Ternary nanocomposites of Au/CuS/TiO for an ultrasensitive photoelectrochemical non-enzymatic glucose sensor.

A novel and highly sensitive photoelectrochemical biosensor for the detection of glucose based on ternary nanocomposites of Au/CuS/TiO2 (Au/CuS/TiO2) has been fabricated. Highly ordered TiO2 nanotube arrays (TiO2 NTs) were prepared by anodization of Ti foils, and CuS nanoparticles (NPs) and Au NPs were deposited on TiO2 NTs by the successive ionic layer adsorption and reaction (SILAR) method. The resultant Au/CuS/TiO2 exhibited excellent photoelectrochemical behavior as a glucose sensor under white light illumination due to the remarkable photocatalytic capabilities of TiO2 and CuS, and the surface plasmonic resonance (SPR) effect of Au NPs.

New Insight into Procedure of Interface Electron Transfer through Cascade System with Enhanced Photocatalytic Activity.

Recombination of photogenerated electron-hole pairs is extremely limited in the practical application of photocatalysis toward solving the energy crisis and environmental pollution. A rational design of the cascade system (i.e.

A novel "dual-potential" ratiometric electrochemiluminescence DNA sensor based on enhancing and quenching effect by G-quadruplex / hemin and Au-Luminol bifunctional nanoparticles.

An ultrasensitive and stable "dual-potential" ratiometric electrochemiluminescence (ECL) sensor is reported for specific DNA, the femtomolar detection limit (0.12 fM, S/N = 3) and high selectivity insure its potential applications in cancer biomarkers searching or monitoring. The excellent performance of the sensor comes from simultaneously fabricated layer by layer structure "target DNA + Hemin / Au-Luminol NPs / DNA* / sl DNA / TGA / QDs / MWNTs / GCE" mode which was based on the enhancing effect of luminol by G-quadruplex / hemin and Au nanoparticles and the quenching effect of CdSe/ZnS by G-quadruplex / hemin.

Encapsulation of Dual-Emitting Fluorescent Magnetic Nanoprobe in Metal-Organic Frameworks for Ultrasensitive Ratiometric Detection of Cu.

An effective dual-emission fluorescent metal-organic framework (MOF)-based nanoprobe has been established for ultrasensitive and rapid ratiometric detection of Cu . Such a nanoprobe was prepared by encapsulating fluorescein isothiocyanate (FITC), and Eu(III) complex-functionalized Fe O into the zeolitic imidazolate framework material (ZIF-8). In this nanoprobe, FITC was used as a reference signal, thus improving the influence of external uncertainties.

Preparation of GO-COOH/AuNPs/ZnAPTPP nanocomposites based on the π-π conjugation: Efficient interface for low-potential photoelectrochemical sensing of 4-nitrophenol.

The GO-COOH/AuNPs/ZnAPTPP nanocomposites were constructed using zinc monoamino porphyrin (ZnAPTPP) through π-π conjugation with carboxylated graphene oxide (GO-COOH) loaded with Au nanoparticles (AuNPs). Prepared materials were characterized by H NMR spectra, UV-vis absorption spectroscopy and electrochemical impedance spectroscopy. ITO electrode surface was modified with the prepared nanocomposites showed a good photocurrent response when the bias potential, -0.

Behaviors of the Interfacial Consecutive Multistep Electron Transfer Controlled by Varied Transition Metal Ions in Porphyrin Cores.

Almost all life activities involve the process of multistep electron transfer (ET) which occurs on biomembrane. Metalloporphyrins (MTPPs) are a class of molecules which are closely related to life course. Here, the n-step (n = 1, 2) ET behaviors controlled by different metal ions in porphyrin cores were investigated by thin-layer cyclic voltammetry (TLCV).

Fe PO -Encapsulated Reverse Energetic ZnO/Fe O Heterojunction Nanowire for Enhanced Photoelectrochemical Oxidation of Water.

Zinc oxide is regarded as a promising candidate for application in photoelectrochemical water oxidation due to its higher electron mobility. However, its instability under alkaline conditions limits its application in a practical setting. Herein, we demonstrate an easily achieved wet-chemical route to chemically stabilize ZnO nanowires (NWs) by protecting them with a thin layer Fe O shell.

Resonance energy transfer based electrochemiluminescence and fluorescence sensing of riboflavin using graphitic carbon nitride quantum dots.

Graphitic carbon nitride quantum dots (g-CNQDs) are rarely used in the field of electrochemiluminescence. In this paper, g-CNQDs have a strong and stable electrochemiluminescence (ECL) signal generated in the presence of co-reactant KSO. The ECL signal of g-CNQDs was quenched by the mechanism of resonance energy transfer (RET) between donor g-CNQDs and receptor riboflavin (RF) that is proved by UV-vis absorption spectroscopy, electrochemiluminescence and fluorescence emission spectroscopy analysis technology.

High-throughput and ultratrace naked-eye colorimetric detection of Au based on the gold amalgam-stimulated peroxidase mimetic activity in aqueous solutions.

Herein, we present a catalysis-based, label-free, and efficient strategy for a rapid, high-throughput, highly selective and ultrasensitive naked-eye colorimetric assay of Au in aqueous solutions, based on the gold amalgam-stimulated peroxidase mimetic activity.

Ultratrace Naked-Eye Colorimetric Detection of Hg in Wastewater and Serum Utilizing Mercury-Stimulated Peroxidase Mimetic Activity of Reduced Graphene Oxide-PEI-Pd Nanohybrids.

Herein, we developed a general strategy for rapid, highly selective, and ultratrace naked-eye colorimetric detection of Hg in aqueous solutions. Two dimensional rGO/PEI/Pd nanohybrids, where rGO, PEI, and Pd were referred to as reduced graphene oxide, polyethylenimine, and Pd nanoparticles, respectively, were synthesized and used as mimetic peroxidase for selective and ultrasensitive detection of Hg in water and human serum samples. In the presence of mercury ions, the peroxidase mimetic activity of rGO/PEI/Pd nanohybrids was found to be stimulated and enhanced significantly, which promoted the effective oxidation and color change of 3,3',5,5'-tetramethylbenzidine (TMB) in solution to dark blue that was detected by the naked-eye and the absorption spectroscopic method.

Assembly of g-CN-based type II and Z-scheme heterojunction anodes with improved charge separation for photoelectrojunction water oxidation.

Graphitic carbon nitride (g-CN) has been widely studied as a metal-free photocatalyst, leading to some excellent results; however, the rapid recombination of photogenerated charge carriers substantially limits its performance. Here, we establish two types of g-CN-based heterojunction (type II and nonmediator assisted Z-scheme) photoanodes on a transparent conducting substrate via coupling with rod-like and nanoparticulate WO, respectively. In these composites, g-CN film grown by electrophoretic deposition of exfoliated g-CN serves as the host or guest material.

Electrochemiluminescence behavior of meso-tetra(4-sulfonatophenyl)porphyrin in aqueous medium: its application for highly selective sensing of nanomolar Cu(2.).

The cathodic electrochemiluminescence (ECL) behavior of meso-tetra(4-sulfonatophenyl)porphyrin (TSPP) with potassium peroxydisulfate (K2S2O8) as the coreactant in aqueous solution with strong and stable emission was exploited to determine Cu(2+) down to nanomolar concentration. Two possible reaction mechanisms have been proposed to understand the generation of ECL by the TSPP/K2S2O8 system. The effects of the concentration of TSPP and K2S2O8, pH of the medium, and scan rate on the ECL intensity were studied in detail.

Comparative study on the interfacial electron transfer of zinc porphyrins with meso-π-extension at a 2(n) pattern.

Three zinc-tetraarylporphyrins were prepared in order to investigate the effects of systematic meso-π-extension on the redox behaviors and interfacial electron transfer kinetics. The meso-π-extension increased at a 2(n) pattern, where 2(n) was the benzene ring number in an aryl group and the aryl group represented phenyl, naphthyl and pyrenyl group, respectively. The structures of zinc-tetraarylporphyrins and hydroquinone were optimized by using density functional theory.

A novel electrochemical sensor based on zirconia/ordered macroporous polyaniline for ultrasensitive detection of pesticides.

A simple and mild strategy was proposed to develop a novel electrochemical sensor based on zirconia/ordered macroporous polyaniline (ZrO2/OMP) and further used for the detection of methyl parathion (MP), one of the organophosphate pesticides (OPPs). Due to the strong affinity of phosphate groups with ZrO2 and the advantages of OMP such as high catalytic activity and good conductivity, the developed sensor showed a limit of detection as low as 2.28 × 10(-10) mol L(-1) (S/N = 3) by square-wave voltammograms, and good selectivity, acceptable reproducibility and stability.