Accelerated Fenton degradation of azo dye wastewater via a novel Z-scheme CoFeN-g-C3N4 heterojunction photocatalyst with excellent charge transfer under visible light irradiation.

A novel Z-scheme heterostructure photocatalyst, CoFeN-g-C3N4 (CFN-CN), was prepared by a simple strategy, and its heterostructure and a photo-Fenton system were used to synergistically catalyze the degradation of azo dyes. The experimental results showed that the CFN-CN1 heterojunction exhibited superior photocatalytic degradation performance, and the degradation rate of Methyl Orange (MO) reached 96.8% in 40 min. The degradation rate constants were 11.8 and 2.81 times those of CN and CFN, respectively. CFN-CN1 also shows excellent catalytic degradation performance for other azo dyes (Congo Red (CR), Acid Orange 7 (AO7), Mordant Black 17 (MB17) and Acid Red B (ARB)), and the degradation efficiencies all exceeded 90%. Furthermore, the addition of inorganic anions (Cl-, HCO3- and SO42-) affects the degradation of azo dyes, especially HCO3- which significantly promotes the degradation of MO. The radical trapping experiments and EPR results indicated that superoxide radicals (˙O2-) and hydroxyl radicals (˙OH) were the main active species. The above research reveals that the CFN-CN heterojunction synergistic photo-Fenton system may provide new hints for the degradation and removal of azo dyes from wastewater.

The Piezo-Fenton synergistic effect of ferroelectric single-crystal BaTiO3 nanoparticles for high-efficiency catalytic pollutant degradation in aqueous solution.

Nano-ferroelectric materials have excellent piezoelectric performance and can degrade organic dye by ultrasonic vibration in an aqueous solution. Here, BaTiO3 (BT) nanoparticles were prepared by a sol-gel/hydrothermal method and further applied in dye degradation in wastewater. BT nanoparticles exhibited excellent catalytic performance for organic dye molecule degradation through the piezo-Fenton synergistic effect. It was found that both the degradation efficiency and reaction rate were boosted by the increase of the molecular weight of organic dyes. The degradation efficiency toward different organic dyes exhibited a trend of CR > ABK > TH > RhB > MB > MO. For example, a high piezo-Fenton-catalytic degradation ratio of 82.8% at 5 min and 0.337 min-1 rate constant were achieved for the CR dye solution (10 mg L-1), which were 3.2 and 6.4 times the corresponding values of piezo-catalytic only degradation. These results mainly originate from the intrinsic properties of BT nanoparticles that can enhance the separation of charge and promote the formation of hydrogen peroxide (H2O2) and hydroxyl radicals (·OH) under ultrasonic vibration. Furthermore, the reaction of Fe(II) with H2O2 can further enhance the formation of ·OH, which can accelerate the degradation of organic dyes. These results indicate that the piezo-Fenton synergistic effect may provide a new clue for the development of the wastewater treatment field under mechanical vibration.

Efficient Removal of Chromium(VI) Using a Novel Waste Biomass Chestnut Shell-Based Carbon Electrode by Electrosorption.

Biomass-derived porous carbon materials have a good application prospect in electrosorption because of their low cost, abundant natural resources, and excellent performance. In this work, three-dimensional interconnected structure porous carbon (CPC) was successfully synthesized from waste biomass chestnut shells by carbonization and chemical activation processes. The unique structure of CPC could offer superior double-layer capacitance and excellent conductivity. The as-obtained CPC was applied as an electrosorption electrode. In the deionization experiments, the removal efficiency of the CPC electrode in a 30 mg L-1 chromium(VI) aqueous solution at 1.0 V was 90.5%. The electrosorption follows pseudo-second-order kinetics. The CPC electrode also presented good regeneration performance in the regeneration test. These results demonstrate that the as-prepared carbonaceous material is an ideal material for capacitive deionization electrodes.

Trimetallic Ru@AuPt core-shell nanostructures: The effect of microstrain on CO adsorption and electrocatalytic activity of formic acid oxidation.

It is desirable to unravel the correlation between the geometric and electronic structures and the activity and further prepare high-performance electrocatalysts. Here in this paper, trimetallic Ru@Au-Pt core-shell nanoparticles were prepared by sequential ethanol reduction method, and further subject to characterization of X-ray diffraction, high angle annular dark field transmission electron microscopy, X-ray photoelectron spectroscopy and electrochemical CO stripping. Further analysis based on Williamson-Hall method revealed that the Au/Pt atomic ratio and shell thickness result in apparent variation of micro-strain and CO binding energy of Ru@AuPt nanoparticles, where the CO oxidation peak potential showed an inverted volcano-shape dependence on the microstrain of the metal nanoparticles while the catalytic activity towards electrooxidation of formic acid is linearly dependent on the micro-strain. The best Ru@Au-Pt catalyst delivers a specific activity of 4.14 mA cm-2, which is 52 times that of Pt/C, respectively. This study indicated that the microstrain and stacking fault of metal nanoparticles might be a good descriptor for the catalytic activity and may shed light the rational design, synthesis and surface engineering towards the high-performance electrocatalyst.

Preparation of core-shell PW12@TiO2 microspheres and oxidative desulfurization performance.

A polyoxometalate-based microsphere catalyst has been prepared through the one-step template method using phosphotungstic acid as the core and TiO2 as the shell, denoted as PW12@TiO2. Multiple characterisation methods namely FT-IR, XRD, XPS, Raman, SEM and TEM were used to characterize the resultant materials, and results indicate that the phosphotungstic acid was encapsulated into the TiO2 phase as the core to form the core-shell structure. The resultant composites were used as catalysts for the oxidative desulfurization of a model oil with H2O2 as oxidant and acetonitrile as solvent. Catalyst PW12@TiO2 exhibited good catalytic activity, with 99.9% S-removal of dibenzothiophene after 60 min under the optimum conditions. Leaching and recycling experiments revealed that the PW12@TiO2 catalyst has excellent recyclability, and there was no significant decrease in S-removal after seven cycles under identical reaction conditions, which could be attributed to the fabrication of the core-shell structure, thus inhibiting the loss in the active sites.

Unraveling the Impact of Ether and Carbonate Electrolytes on the Solid-Electrolyte Interface and the Electrochemical Performances of ZnSe@C Core-Shell Composites as Anodes of Lithium-Ion Batteries.

The recognition of the solid electrolyte interface (SEI) between the electrode materials and electrolyte is limiting the selection of electrode materials, electrolytes, and further the electrochemical performance of batteries. Herein, we report ZnSe@C core-shell nanocomposites derived from ZIF-8 as anode materials of lithium-ion batteries, the electrochemical performances, and SEI films formed on ZnSe@C in both ether and carbonate electrolytes. It is found that ZnSe@C delivers a reversible capacity of 617.1 mA h·g-1 after 800 cycles at 1 A·g-1 in the ether electrolyte, much higher than that in the carbonate electrolyte. Both ex situ X-ray diffraction and X-ray photoelectron spectroscopies reveal that stable SEI films are formed on ZnSe@C in the ether electrolyte while selenium is involved in the formation of SEI films and further dissolved into the carbonate electrolyte because of the concurrent decomposition of electrolytes and insertion of Li+ into ZnSe, which differentiates between the cycling performances of ZnSe@C composites in ether and carbonate electrolytes.

CoSe2 Nanoparticles Encapsulated by N-Doped Carbon Framework Intertwined with Carbon Nanotubes: High-Performance Dual-Role Anode Materials for Both Li- and Na-Ion Batteries.

It is of fundamental and technological significance to develop dual-role anode materials for both lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) with high performance. Here, a composite material based on CoSe2 nanoparticles encapsulated in N-doped carbon framework intertwined with carbon nanotubes (CoSe2@N-CF/CNTs) is prepared successfully from cobalt-based zeolitic imidazolate framework (ZIF-67). As anode materials for LIBs, CoSe2@N-CF/CNTs composites deliver a reversible capacity of 428 mAh g-1 even after 500 cycles at a current density of 1 A g-1 with almost 100% Coulombic efficiency. The charge and discharge mechanisms of CoSe2 are characterized using ex situ X-ray diffraction and Raman analysis, from which the lithiation products of CoSe2 are found to be Li x CoSe2 and Li2Se, which are further converted to CoSe2 upon delithiation. The CoSe2@N-CF/CNTs composites also demonstrate excellent electrochemical performance as anode materials for SIBs with a carbonate-based electrolyte, with specific capacities of 606 and 501 mAh g-1 at 0.1 and 1 A g-1 in the 100th cycle. The electrochemical performance of the anode materials is further studied by pseudocapacitance and galvanostatic intermittent titration technique (GITT) measurements. This work may be exploited for the rational design and development of dual-role anode materials for both Li- and Na-ion batteries.

Anomalous Effect of Intramolecular Charge Transfer on the Light Emitting Properties of BODIPY.

A new way to approaching highly emissive BODIPY dyes in both solution and solid state is achieved by introducing intramolecular charge transfer (ICT). A hybrid excited state that shows behaviors of both the ICT excited state and local excited state is discovered to be beneficial in avoiding the disturbance from the rotation vibration of the flexible phenyl substituents. Thus, the nonradiative transition process is suppressed, and the fluorescence efficiency goes up. By modification of the excited state, we realize emission enhancement of crystalline BODIPY derivatives with a PLQY from 0.08 to 0.27, and the compound expresses a good potential application prospect in organic semiconductors.

Characterization and mechanism study of micrometer-sized secondary assembly of ß-cyclodextrin.

We herein report a ß-cyclodextrin-based secondary assembly (ß-CD SA) obtained from an aqueous solution. It was found that the addition of a very small amount of organic molecule 2-phenyl-5-(4-diphenylyl) 1,3,4-oxadiazole (PBD) into an aqueous solution of 10 mM ß-CD led to the formation of a micrometer-sized rodlike SA, which made the mixture turbid immediately. After careful characterization, the structure and the formation mechanism of the ß-CD SA were suggested. PBD first induces ß-CDs to form rigid nanotubes through head-to-head or tail-to-tail routes. Using the "solid" nanotubes as recrystallization centers, other ß-CDs assembled to channel in the c axis direction and hexagonally aligned in the b axis direction, leading to the formation of a ß-CD SA. In the ß-CD SA, most of the ß-CDs were not occupied by PBD. In the course of formation , intermolecular hydrogen-bonding plays a prominent role. The results reported herein would be helpful in constructing cyclodextrin-based architectures in water.

Radiolytic syntheses of nanoparticles in supramolecular assemblies.

Ionizing radiation is a powerful method in the syntheses of nanoparticles (NPs). The application of ionizing radiation in supramolecular assemblies can afford us more unique conditions to control the composition and morphology of the NPs. So far, most work focused on water-in-oil (W/O) microemulsions or reversed micelles. In this supramolecular organization, it has been proved that the effects of many conditions on the yield of e(aq)(-) play a key role, remarkably different from the mechanism in routine chemical method. Besides, some supramolecular assemblies of cyclodextrins and ionic liquids have been used in the syntheses of NPs by ionizing radiation, and many novel and interesting phenomena appeared. This review is intended to underline the three significant aspects of the radiolytic syntheses of NPs in supramolecular assemblies.

Cyclodextrin-based aggregates and characterization by microscopy.

Cyclodextrin-based aggregates have been widely investigated with microscopies such as STM, AFM, SEM, TEM, and fluorescent microscopy to obtain the direct morphology and structure of samples. In the present review, we discuss various types of cyclodextrin aggregates, that is, native and modified cyclodextrins, inclusion complexes and their aggregates of cyclodextrins, cyclodextrin rotaxanes and polyrotaxanes, cyclodextrin nanotubes and their secondary assembly, and other high-order aggregates of cyclodextrins. Especially, we focus on the use of microscopy to characterize above aggregates. The application of modern microscopy tools promotes the investigation on cyclodextrins.

Formation of solid and hollow cuprous oxide nanocubes in water-in-oil microemulsions controlled by the yield of hydrated electrons.

A local ordered structure constructed from solid Cu(2)O nanocubes was obtained by the radiolytic reduction of Cu(NO(3))(2) in a water-in-oil (W/O) microemulsion composed of Triton X-100, n-hexanol, cyclohexane, and water in the presence of ethylene glycol (EG). However, when Triton X-100 was replaced with Brij 56 in the microemulsion, hollow Cu(2)O nanocubes were synthesized. The addition of toluene into the Brij 56 system could decrease the ratio of hollow nanocubes. It was suggested that the balance between the reduction rate of Cu(2+) depending on the yield of hydrated electrons (e(aq)(-)) and the escape rate of the mixed solvent determined their final morphologies. The presence of EG influenced the rigidity of the interface of the microemulsion and thus the above balance, which resulted in the different morphologies of Cu(2)O nanoparticles in the Brij 56-based microemulsion.

Formation of nanoparticles in water-in-oil microemulsions controlled by the yield of hydrated electron: the controlled reduction of Cu2+.

In the water-in-oil (W/O) microemulsions based on nonionic surfactants, i.e., Brij 30, Brij 56, or Triton X-100, the omega value (molar ratio of water to surfactant), anion, and surfactant could remarkably affect the radiolytic reduction of Cu2+ and the morphologies of the reduction products simultaneously. The addition of toluene or naphthalene could transform the reduction products from copper to cuprous oxide in the Brij 56-based microemulsion, and the efficiency of naphthalene was obviously higher than that of toluene. After the effects of pH value and cosurfactant were excluded, it could be concluded that the effects of the omega value, the anion, and the structure of the surfactant on the yield of hydrated electrons (eaq-) play a key role in the radiolytic reduction of Cu2+. It was also suggested that the morphology of the reduction product may be controlled by the yield of eaq-.

[Interaction of surface active fluorescence probes and bovine serum albumin].

The binding between two surface-active substituted 3H-indole fluorescence probes, i. e., iodo-dihexadecyl methyl-2-(p-dodecyl amino phenyl)-3, 3-dimethyl-5-carboethoxy-3H-indole ammonium and iodo-dimethyloctadecyl-2-(p-dodecyl amino phenyl)-3,3-dimethyl-5-carboethoxy-3H-indole ammonium, and bovine serum albumin (BSA) in aqueous solution was studied using fluorescence. The binding constant and binding site number of molecule 1 and molecule 2 with BSA were obtained. It was confirmed that electrostatic interaction is the primary driving force for the combination of BSA with molecule 1 or molecule 2. According to the Förster resonance energy transfer theory, the distances between molecule 1, molecule 2 and tryptophan of BSA were calculated to be 2.90 nm and 4.02 nm, respectively.

[Synthesis of substituted 3H-indole quaternary ammonium salt and study on its interaction with bovine serum albumin by fluorescence].

A substituted 3H-indole quaternary ammonium molecule was designed and synthesized using hexamethylphosphoramide (HMPA) as a solvent. The products were purified and characterized by IR, 1H-NMR, MS and elemental analysis. The binding reaction of this compound with bovine serum albumin (BSA) in aqueous solution was studied using fluorescence. Their binding constant is Ka = 1.995 x 10(5) dm3 x mol(-1) and the binding site number is n = 1.12. It is confirmed that the combination is a single static quenching process.

[Investigation on the spectral characteristics and existing state of a substituted 3H-indole molecular probe in triton X-100 reverse micelle].

The interactions between a fluorescent molecular probe, i. e., [2-(p-hexylamino) phenyl-3, 3-dimethyl-5-ethoxycarbonyl-3H-indole] methyldioctadecylammonium iodide (A) and Triton X-100/heptane/hexanol/water reverse micelle have been investigated by spectroscopy. Micropolarity of the environment, fluorescence anisotropy parameter and the pH effect of A in Triton X-100 reverse micelle were determined. Furthermore, the state of water in reverse micellar systems was studied by FTIR. According to the above experimental results, some information on the structure of Triton X-100 reverse micelle was obtained and the probable site of A in this system was discussed.

Size-controlled preparation of Cu2O octahedron nanocrystals and studies on their optical absorption.

We report herein the size-controlled preparation of monodispersed cuprous oxide octahedron nanocrystals smaller than 100 nm. The method is based on the reduction of copper nitrate in Triton X-100 water-in-oil (w/o) microemulsions by gamma-irradiation. The average edge length of the octahedron-shaped nanocrystals varies from 45 to 95 nm as a function of the dose rate. The quantum confinement effect was illustrated by the blueshift in the optical absorption. In addition, the growth process was also traced by absorption spectra.

Extraction of inorganic acids with neutral phosphorus extractants based on a reverse micelle/microemulsion mechanism.

The extraction of inorganic acids such as HCl, HNO(3), H(2)SO(4), and HClO(4) has been investigated in three neutral phosphorus compound systems, i.e., tri-n-butyl phosphate (TBP), di-isoamylmethyl phosphonate (DiAMP), and trialkylphosphine oxide (TRPO, C(6)-C(8)), using n-heptane as a diluent. The techniques of electrical conductivity, Fourier transform infrared (FTIR) spectroscopy, 1H NMR, and dynamic laser scattering (DLS) were selected to characterize the organic phases. The results indicate that the interaction between acids and neutral phosphorus compounds follows a molecule-ion combination mechanism. When the acid in the organic phase reaches a certain concentration, the molecular-ion species have a tendency to self-assemble and form reverse micelles/microemulsions (W/O). The further increase of the acid concentration leads the organic phase to split into two layers. Extractants and acids are mainly located in the down layer, in which aggregations are formed. The tendency to form microemulsions follows TRPO > DiAMP > TBP.

[Studies on the formation of cyclodextrin nanotube by fluorescence and anisotropy measurements].

Steady-state fluorescence and anisotropy measurements have been used to investigate the interaction of 2,2'-biquinoline (BQ) and 1,1'-(methylenedi-1,4-phenylene)bismaleimide (MDP-BMI) with alpha-, beta-, and gamma-cyclodextrins (CDs). It was found that the reaction patterns between fluorescence molecules and CDs are remarkably different. They can form a simple inclusion complex with alpha-CD, while nanotubes can be formed in the presence of gamma-CD. Moreover, MDP-BMI can form nanotube with beta-CD at higher concentration.

[Study on the photofluorescence of Eu(III) and long chain fatty acid complexes].

The complexes having the compositions of Eu(L1)(3)2H2O,Eu(L1)3phen,Eu(L2)(3)2H2O,Eu(L2)3phen (phen = 1,10-phenathroline,L1 = Dodecanoic acid, L2 = Stearic acid) were synthesized and characterized by elemental analysis and FTIR spectra. Their fluorescence spectra, UV spectra and TEM (Transmission Electron Microscope) have been investigated. The results show that the 5D0-7F1 and 5D0-7F2 transition of Eu(III) are observed in the emission spectrum of the particles at room temperature. As good photoluminescent materials, they may be useful in the regions of EL (Electroluminescence) or macromolecule composite materials doped with rare earth.