Precursor engineering towards orange- and red-emissive carbon dots for LEDs with tunable emission colors.

Carbon dots (CDs) have attracted significant research interest due to their great potential in optoelectronic applications. Although various CDs have been synthesized the "bottom-up" pathway, few studies have focused on understanding the origins of the structural and optical diversities of CDs. In this study, two benzenoid acids with a slight structural variation (, 9-oxo-9-fluorene-2,7-dicarboxylic acid (FR) and 4,4'-biphenyl dicarboxylic acid (BP)) are employed as precursors, yielding orange- and red-emissive CDs with quantum yields of 43.

The Improved Microwave Absorption Performance of the 3D Porous (Ni@NO-C)/NO-C Composite Absorber.

Microwave absorbers that are lightweight and have good stability and high efficiency have attracted much attention for their applications in many contemporary fields. In this work, a 3D porous (Ni@NO-C)/NO-C composite absorber was prepared using a wet chemistry method with Ni chains and melamine as precursors, in which NO-C (N,O-doped carbon)-encapsulated Ni particles are homogenously dispersed in the 3D porous networks of NO-C in the form of (Ni@NO-C) chains. The special microstructure of the as-prepared material is proven to be beneficial for the improvement of its microwave absorption performance.

Efficient Photocatalytic Degradation of Tetracycline on the MnFeO/BGA Composite under Visible Light.

In this work, the MnFeO/BGA (boron-doped graphene aerogel) composite prepared via the solvothermal method is applied as a photocatalyst to the degradation of tetracycline in the presence of peroxymonosulfate. The composite's phase composition, morphology, valence state of elements, defect and pore structure were analyzed by XRD, SEM/TEM, XPS, Raman scattering and N adsorption-desorption isotherms, respectively. Under the radiation of visible light, the experimental parameters, including the ratio of BGA to MnFeO, the dosages of MnFeO/BGA and PMS, and the initial pH and tetracycline concentration were optimized in line with the degradation of tetracycline.

The Various Packing Structures of Tb@C (I, II) Isomers in Their Cocrystals with Ni(OEP).

Soot-containing terbium (Tb)-embedded fullerenes were prepared by evaporation of TbO-doped graphite rods in an electric arc discharge chamber. After 1,2,4-trichlorobenzene extraction of the soot and rotary evaporation of the extract, a solid product was obtained and then dissolved into toluene by ultrasonication. Through a three-stage high-pressure liquid chromatographic (HPLC) process, Tb@C (I, II) isomers were isolated from the toluene solution of fullerenes and metallofullerenes.

Influences of different surface oxygen species on oxidation of toluene and/or benzene and their reaction pathways over Cu-Mn metal oxides.

Catalytic oxidation is considered as the most effective and economical method to remove low concentration volatile organic compounds (VOCs). Activation of oxygen to form active oxygen species on metal oxides catalyst plays a key role in the process. Three copper-manganese oxide catalysts with cubic CuMnO phases were prepared by microwave heating (CM-MW), sol-gel (CM-SG) and co-precipitation (CM-CP) methods, and applied for the elimination of toluene and benzene as representative aromatic VOCs.

Polymethyl(1-Butyric acidyl)silane-Assisted Dispersion and Density Gradient Ultracentrifugation Separation of Single-Walled Carbon Nanotubes.

Individual single-walled carbon nanotubes (SWNTs) with distinct electronic types are crucial for the fabrication of SWNTs-based electronic and magnetic devices. Herein, the water-soluble polymethyl(1-butyric acidyl)silane (BA-PMS) was synthesized via the hydrosilylation reaction between 3-butenoic acid and polymethylsilane catalyzed by 2,2'-azodibutyronitrile. As a new dispersant, BA-PMS displayed a quite good dispersing capacity to arc-discharged SWNTs and moderate selectivity for metallic species.

HoC Cluster with Flexible Configurations inside a Large -C Cage.

Carbide clusterfullerenes (CCFs) have been of great concern due to their potential applications in materials science, in which the internal carbide cluster plays vital roles in the stability and properties of CCF. However, there still remains a debate about what configuration is ideal for the internal carbide cluster. In this work, we isolated two isomers (I and II) of HoC and studied them by means of mass spectrometry, UV-vis-NIR spectroscopy, and cyclic/differential pulse voltammetry.

The Efficient Photocatalytic Degradation of Organic Pollutants on the MnFeO/BGA Composite under Visible Light.

The MnFeO/BGA (boron-doped graphene aerogel) composite was prepared by hydrothermal treatment of MnFeO particles, boric acid, and graphene oxide. When applied as a photo-Fenton catalyst for the degradation of rhodamine B, the MnFeO/BGA composite yielded a degradation efficiency much higher than the sum of those of individual MnFeO and BGA under identical experimental conditions, indicating a strong synergetic effect established between MnFeO and BGA. The catalytic degradation of rhodamine B was proved to follow pseudo first-order kinetics, and the apparent reaction rate constant on the MnFeO/BGA composite was calculated to be three- and seven-fold that on BGA and MnFeO, respectively.

Determination of Organophosphorus Pesticides Using Solid-Phase Extraction Followed by Gas Chromatography-Mass Spectrometry.

In this study, a method was developed for determination of three organophosphorus pesticides (OPPs) using graphene aerogel solid-phase extraction (SPE) combined with gas chromatography-mass spectrometry (GC-MS). The experimental results showed that the target analytes could be extracted on packed SPE cartridges and then eluted with tetrahydrofuran. The final sample solution was analyzed by GC-MS, which demonstrated good linearity between 0.

Enhanced Catalytic Oxidation of Toluene over Manganese Oxide Modified by Lanthanum with a Coral-Like Hierarchical Structure Nanosphere.

Coral-like lanthanum manganese oxides (LaMnO) with a hierarchical structure nanosphere were successfully prepared using a simple method, which presented a high-efficiency catalytic performance for toluene combustion. Among them, LaMnO with the MnO phase exhibits superior catalytic activity, such as a lower value (218 °C), excellent HO resistance, and catalytic stability. The effects of La addition on the bulk and surface physicochemical properties of LaMnO were investigated by sorts of characterization including X-ray diffraction, scanning electron microscopy, transmission electron microscopy, N adsorption-desorption, temperature-programmed reduction with H, temperature-programmed desorption of O, X-ray photoelectron spectroscopy, and so forth.

Favorite Orientation of the Carbon Cage and a Unique Two-Dimensional-Layered Packing Model in the Cocrystals of Nd@C(I,II) Isomers with Decapyrrylcorannulene.

To date, the experimental studies on Nd-based metallofullerenes are only limited to spectroscopic characterizations. In this work, the molecular structures of Nd@C(I,II) isomers, including the isomeric symmetry of the C cage and the position of endohedral Nd atom, as well as their unique two-dimensional (2D)-layered crystallographic packing structures were initially and unambiguously elucidated, based on the X-ray structural analyses of the cocrystals of Nd@C(I) or Nd@C(II) with cocrystallizing agent decapyrrylcorannulene (DPC). In the V-shaped unit cell, the endohedral Nd atom prefers a site as far away from the DPC molecules as possible because of the unevenly distributed charge on the C cage mainly related to the charge transfers from the endohedral Nd atom, cocrystallizing agent DPC, and solvent toluene molecules to the C cage.

HoO-C: Highly Stretched Cluster Dictated by a Giant Cage and Unexplored Isomerization.

For endohedral metallofullerenes (EMFs), it has been well established that the cage shape and size should match those of the endohedral cluster. As a result, sufficient cluster-cage interaction can be achieved, which is essential for mutual stabilization. Nevertheless, how a small endohedral cluster nests in a giant fullerene has been less explored.

Dispersion of arc-discharged single-walled carbon nanotubes using the natural α-amino acid derivative -dodecanoyl leucinate.

The natural α-amino acid derivate -dodecanoyl leucinate was synthesized Schotten-Baumann reaction and alkali treatment, and was applied to the dispersion of arc-discharged single-walled carbon nanotubes (SWNTs). Optical absorption and Raman scattering spectra as well as AFM observation confirmed the effective individualization and selective dispersion of SWNTs. Moreover, charge transfer from -dodecanoyl leucinate to SWNTs was evidenced by FT-IR and Raman scattering spectroscopic analyses.

Preparation of reduced graphene oxide nanosheet/FeO/nitrogen-doped carbon layer aerogel as photo-Fenton catalyst with enhanced degradation activity and reusability.

In this manuscript, a novel reduced graphene oxide nanosheet/FeO/nitrogen-doped carbon layer (rGS/FeO/NCL) aerogel with FeO NPs sandwiched between rGS and NCL was prepared via a two-step method. Their catalytic performance was evaluated in a photo-Fenton degradation of rhodamine B. It was found that rGS/FeO/NCL aerogel represented higher degradation activity than the sum of rGS/NCL support and FeO NPs, suggesting synergistic effect was established between support and reactive species.

Determination of seven pyrethroid pesticide residues in vegetables by gas chromatography using carboxylated multi-walled carbon nanotubes as dispersion solid phase extraction sorbent.

A novel carboxylated multi-walled carbon nanotubes (MWCNTs-COOH) dispersive solid phase extraction (d-SPE) method combined with gas chromatography (GC) with an electron capture detector (ECD) was developed for the determination of seven pyrethroid pesticides in cucumber, spinach, eggplant, tomato and carrot. We optimised d-SPE conditions including the type and volume of the extractant, the type and amount of the sorbent, and shaking time. Under the optimal conditions, the linear range was from 2.

An Explosive Bomb-Inspired Method to Prepare Collapsed and Ruptured Fe O /Nitrogen-Doped Carbon Capsules as Catalyst Support.

Compared with integrated capsules, ruptured ones have better mass diffusion and transport properties due to large gaps in the shells. However, most studies focus on integrated capsules, whereas little attention has been paid to the ruptured counterparts. Herein, an explosive bomb-inspired method was employed to prepare collapsed and ruptured Fe O /nitrogen-doped carbon (CR-Fe O /NC) capsules by using polystyrene (PS) nanoparticles (NPs) as a hard template, and polypyrrole (PPy) with embedded Prussian blue (PB) NPs as the shell.

Adamantylidene Addition to M N@I -C (M=Sc, Lu) and Sc N@D -C : Synthesis and Crystallographic Characterization of the [5,6]-Open and [6,6]-Open Adducts.

Additions of adamantylidene (Ad) to M N@I -C (M=Sc, Lu) and Sc N@D -C have been accomplished by photochemical reactions with 2-adamantyl-2,3'-[3H]-diazirine (1). In M N@I -C , the addition led to rupture of the [6,6]- or [5,6]-bonds of the I -C cage, forming the [6,6]-open fulleroid as the major isomer and the [5,6]-open fulleroid as the minor isomer. In Sc N@D -C , the addition also proceeded regioselectively to yield three major isomeric Ad mono-adducts, despite the fact that there are nine types of C-C bonds in the D -C cage.

D(23)-C versus ScC@D(23)-C: Impact of Endohedral ScC Doping on Chemical Reactivity in the Photolysis of Diazirine.

We compared the chemical reactivity of D(23)-C and that of ScC@D(23)-C, both having the same carbon cage geometry, in the photolysis of 2-adamantane-2,3'-[3H]-diazirine, to clarify metal-atom doping effects on the chemical reactivity of the carbon cage. Experimental and computational studies have revealed that the chemical reactivity of the D(23)-C carbon cage is altered drastically by endohedral ScC doping. The reaction of empty D(23)-C with the diazirine under photoirradiation yields two adamantylidene (Ad) adducts.

The Unanticipated Dimerization of Ce@C (9)-C upon Co-crystallization with Ni(octaethylporphyrin) and Comparison with Monomeric M@C (9)-C (M = La, Sc, and Y).

We report that Ce@C (9)-C forms a centrosymmetric dimer when co-crystallized with Ni(OEP) (OEP = octaethylporphyrin dianion). The crystal structure of {Ce@C (9)-C } ⋅2[Ni(OEP)]⋅4 C H shows that a new C-C bond with a bond length of 1.605(5) Å connects the two cages.

A Ternary Polyaniline/Active Carbon/Lithium Iron Phosphate Composite as Cathode Material for Lithium Ion Battery.

Lithium iron phosphate (LiFePO4) has been evaluated as the most promising cathode material for the next generation lithium-ion batteries because of its high operating voltage, good cycle performance, low cost, and environmentally friendly safety. However, pure LiFePO4 shows poor reversible capacity and charge/discharge performance at high current density. Many methods including optimization of particle size, introduction of coating carbon and conductive polymer, and the doping of metal and halogen ions have been developed to improve its electrochemical performance.

Isomers of IC70BA and Their Photovoltaic Performance in Polymer Solar Cells.

Indene-C70 derivatives were synthesized, including indene-C70 mono-adduct (IC70MA), indene-C70 bis-adduct (IC70BA) and indene-C70 tris-adduct (IC70TA). All as-prepared fullerene adducts are in fact a mixture of isomers. The IC70BA mixture was further separated by high-performance liquid chromatography (HPLC) and two different IC70BA isomers were obtained.

Engineering the work function of buckled boron α-sheet by lithium adsorption: a first-principles investigation.

First-principles density functional theory calculations were performed to study the effect of Li adsorption on the structural and electronic properties, particularly the work function, of boron α-sheet. The calculated binding energies indicated that boron α-sheet could be well stabilized by the adsorption of Li atoms. Furthermore, the work functions of Li-adsorbed boron α-sheets were observed to decrease drastically with increasing Li coverage.

Regioselective synthesis and molecular structure of the first derivative of praseodymium-containing metallofullerenes.

Regioselective cycloaddition of adamantylidene carbene to Pr@C(2v)(9)-C82 affords the first derivative of praseodymium-containing metallofullerenes. Single-crystal X-ray crystallographic data in combination with theoretical studies demonstrate that the addition is dictated by the single metal ion encapsulated inside the fullerene cage.

Preparation and characterization, stable bismaleimide-triarylamine polymers with reversible electrochromic properties.

A series of novel polyimides were synthesized from bismaleimide containing different diaminetriarylamines by Michael addition reaction. The prepolymer is readily soluble in many common organic solvents, such as CHCl3, Tetrahydrofuran (THF) and N, N-dimethyl formamide (DMF). Prepolymers can be solution-cast into transparent, tough, and flexible films.

An experimentally observed trimetallofullerene Sm3@I(h)-C80: encapsulation of three metal atoms in a cage without a nonmetallic mediator.

We report the synthesis, isolation, and characterizations of the novel trimetallofullerene Sm3@I(h)-C80. Importantly, the experimental X-ray structure of Sm3@I(h)-C80 verified for the first time that three metal atoms can be stabilized in a fullerene cage without a nonmetal mediator. Furthermore, computational studies demonstrated the electronic features of Sm3@I(h)-C80, which are similar to that of theoretically studied Y3@I(h)-C80.