Phosphotungstic acid immobilized on amino-functionalized TS-1 zeolite as a solid acid catalyst for the synthesis of tributyl citrate

The amino-functionalization of TS-1 zeolite followed by immobilization of phosphotungstic acid(HPW)was presented to prepare a strong solid acid catalyst for the synthesis of bio-based tributyl citrate from the esterification of citric acid and n-butanol.γ-Aminopropyltriethoxysilane(APTES)was first grafted on the TS-1 zeolite via the condensation reactions with surface hydroxyl groups,and subsequently the HPW was immobilized via the reaction between the amino groups and the protons from HPW-forming strong ionic bonding.The Keggin structure of HPW and MFI topology of TS-1 zeolite were well maintained after the modifications.The amino-functionalization generated abundant uniformly distributed active sites on TS-1 for HPW immobilization,which promoted the dispersity,abundance,as well as the stability of the acid sites.The tetrahedrally coordinated framework titanium and non-framework titania behaved as weak Lewis acid sites,and the protons from the immobilized HPW acted as the moderate or strong Brønsted acid sites.An optimized TBC yield of 96.2%(mol)with a conversion of-COOH of 98.1%(mol)was achieved at 150℃for 6 h over the HPW immobilized on amino-functionalized TS-1.The catalyst exhibited good stability after four consecutive reaction runs,where the activity leveled off at still a relatively high level after somewhat deactivation possibly caused by the leaching of a small portion of weakly anchored APTES or HPW.

Integration of Desulfurization and Lithium-Sulfur Batteries Enabled by Amino-Functionalized Porous Carbon Nanofibers

Hydrogen sulfide(H_(2)S)is an industrial exhausted gas that is highly toxic to humans and the environment.Combining desulfurization and fabrication of cathode materials for lithium-sulfur batteries(LSBs)can solve this issue with a double benefit.Herein,the amino-functionalized lotus root-like carbon nanofibers(NH_(2)-PLCNFs)are prepared by the amination of electrospinning carbon nanofibers under dielectric barrier discharge plasma.Selective catalytic oxidation of H_(2)S to elemental sulfur(S)is achieved over the metalfree NH_(2)-PLCNFs catalyst,and the obtained composite S@NH_(2)-PLCNFs is further used as cathode in LSBs.NH_(2)-PLCNFs enable efficient desulfurization(removal capacity as high as 3.46 g H_(2)S g^(−1) catalyst)and strongly covalent stabilization of S on modified carbon nanofibers.LSBs equipped with S@NH_(2)-PLCNFs deliver a high specific capacity of 705.8 mA h g^(−1) at 1 C after 1000 cycles based on the spatial confinement and the covalent stabilization of electroactive materials on amino-functionalized porous carbon matrix.It is revealed that S@NH_(2)-PLCNFs obtained by this kind of chemical vapor deposition leads to a more homogeneous S distribution and superior electrochemical performance to the sample S/NH_(2)-PLCNF-M prepared by the traditional molten infusion.This work opens a new avenue for the combination of environment protection and energy storage.

Adsorption behavior and adsorption mechanism of Cu(Ⅱ) ions on amino-functionalized magnetic nanoparticles

Amino-functionalized magnetic nanoparticle （NH2-MNP） were prepared by a sol-gel approach. The adsorption behavior of Cu（II） ions on NH2-MNP was discussed systematically by batch experiments. The effects of initial Cu（II） ions concentration, time, pH and temperature were investigated. In kinetic studies, the pseudo-second-order model was successfully employed, and the pseudo-first-order model substantiated that Cu（II） adsorption on NH2-MNP was a diffusion-based process. Langmuir model and Dubinin-Radushkevich model （R2〉0.99） were more corresponded with the adsorption isotherm data of Cu（II） ions than Freundlich model. The adsorption capacity was increased with the increment of temperature and pH. NH2-MNP remains excellent Cu（II） recoveries after reusing five adsorption and desorption cycles, making NH2-MNP a promising candidate for repetitively removing heavy metal ions from environmental water samples. According to the results obtained from adsorption activation energy and thermodynamic studies, it can be inferred that the main adsorption mechanism between absorbent and Cu（II） ions is ion exchange-surface complexation.

Self-assembly synthesis of SnNb2O6/amino-functionalized graphene nanocomposite as high-rate anode materials for sodium-ion batteries

A two-dimensional(2 D)SnNb_(2)O_(6)/amino-functionalized graphene(En-RGO)nanocomposite with a representative 2 D-2 D architecture has been constructed by an easy self-assembly approach and firstly investigated as anode materials for secondary sodium-ion batteries.The SnNb_(2)O_(6)nanosheets are evenly anchored with the aminofunctionalized graphene through electrostatic attractive interplay between the negatively charged SnNb_(2)O_(6)and positively charged En-RGO after modification.As a result,a remarkable reversible capacity of 300 mAh·g^(-1)was obtained at 50 mA·g^(-1),and significantly,the En-RGO electrode could also deliver ultra-long calendar life up to1900 cycles with a high reversible capacity of200 mAh·g^(-1)at current of 500 mA·g^(-1).Such excellent electrochemical characteristics can be mainly ascribed to its fast pseudo-capacitive energy storage mechanism,and the capacitive contribution can even reach up to 90%at1.2 mV·s^(-1).

Preparation of Amino-functionalized Guanidinium Ionic Liquid-Modified Magnetic Materials and Application in Solid-Phase Extraction of Pollutants in Water

In the present work,a novel amino-functionalized hexaalkylguanidinium chloride ionic liquid was prepared and grafted on the surface of magnetic materials through polyethyleneimine to enrich polycyclic aromatic hydrocarbons in water in combination with HPLC equipped with an ultraviolet detector.The effect of several parameters on the extraction efficiency was investigated,including the desorption solvent,the amounts of sorbents,the extraction time,the desorption time and the salt amount.Under the optimized conditions,the method validation exhibited good linearity with correlation coefficients above 0.994 in the range of 0.2-300 ng/mL and low limits of detection and quantification of 0.05 and 0.2 ng/mL,respectively.Besides,relative recoveries were in the range of 80-120%,and the intra-day and inter-day repeatability were good with the relative standard deviations of less than 20%.Finally,the guanidinium ionic liquid modified magnetic materials were applied for the extraction of polycyclic aromatic hydrocarbons from real water samples to demonstrate the utility,and the results show that the proposed method has good prospect for effective enrichment and determination of pollutants in water.

Synthesis and optoelectronic properties of amino-functionalized carbazole-based conjugated polymers

A series of alcohol soluble amino-functionalized carbazole-based copolymers were synthesized via Suzuki coupling reaction. The pendent amino groups endow them high solubility in polar solvents, as well as efficient electron injection capability from high work-function metals. The relationships between the photophysical and electrochemical properties and the polymer backbone structure were systematically investigated. These alcohol-soluble carbazole-based copolymers were used as cathode interlayers between the high work-function metal A1 cathode and P-PPV emissive layer in polymer light-emitting diodes with device structure of ITO/PEDOT：PSS/P-PPV/interlayer/A1. The resulting devices exhibited improved performance due to the better electron injection/transporting ability of the designed copolymers from A1 cathode to the light-emitting layer.

Amino-functionalized core-shell magnetic mesoporous composite microspheres for Pb(Ⅱ) and Cd(Ⅱ) removal

Amino-functionalized Fe3O4@mesoporous SiO/ core-shell composite microspheres NH2-MS in created in multiple synthesis steps have been investigated for Pb（Ⅱ） and Cd（Ⅱ） adsorption. The microspheres were characterized by transmission electron microscope （TEM）, scanning electron microscope （SEM）, N2 adsorption-desorption, zeta potential measurements and vibrating sample magnetometer. Batch adsorption tests indicated that NH2-MS exhibited higher adsorption affinity toward Pb（Ⅱ） and Cd（Ⅱ） than MS did. The Langmuir model could fit the adsorption isotherm very well with maximum adsorption capacity of 128.21 and 51.81 mg/g for Pb（Ⅱ） and Cd（Ⅱ）, respectively, implying that adsorption processes involved monolayer adsorption. Pb（Ⅱ） and Cd（Ⅱ） adsorption could be well described by the pseudo second-order kinetics model, and was found to be strongly dependent on pH and humic acid. The Pb（Ⅱ）- and Cd（Ⅱ）-loaded microspheres were effectively desorbed using 0.01 mol/L HC1 or EDTA solution. NH2-MS have promise for use as adsorbents in the removal of Pb（Ⅱ） and Cd（Ⅱ） in wastewater treatment processes.

Amino-functionalized porous PDVB with high adsorption and regeneration performance for fluoride removal from water

Excessive fluoride anions in drinking water are toxic to the health of human beings.In this article,an effective fluoride removal adsorbent on the basis of amino-functionalized porous polydivinylbenzene(PDVB)was prepared through low cost processes,which included solvothermal preparation of porous PDVB and subsequent surface amino-functionalization.The obtained amino-functionalized porous PDVB(A-PDVB)has high surface area of 443 m2 g1 and high adsorption capacity towards fluoride anion up to 105.9 mg g1.Considering adsorbents surface area,the adsorption capacity per unit surface area of A-PDVB is 0.24 mg m2 which is more than 4 times of porous PDVB(0.058 mg m2).The enhanced adsorption performance of A-PDVB was due to amino groups electrostatic interaction coupled with hydrogen bond binding with fluoride anions.In addition,the aminofunctionalized porous PDVB could be regenerated in high efficiency under alkaline conditions.This work not only exhibits the possibility of A-PDVB for application as an environment-friendly adsorbent for fluoride removal but also gives an insight into understanding mechanism of the fluoride anions adsorption onto aminofunctionalized porous PDVB.

Highly reactive and reusable heterogeneous activated carbons-based palladium catalysts for Suzuki-Miyaura reaction

Suzuki-Miyaura reaction of aryl halides with phenylboronic acid using a heterogeneous palladium catalyst based on activated carbons(AC) was systematically investigated in this work. Two different reaction modes(batch procedure and continuous-flow procedure) were used to study the variations of reaction processing. The heterogeneous catalysts presented excellent reactivity and recyclability for iodobenzene and bromobenzene substrates in batch mode, which can be attributed to stabilization of Pd nanoparticles by the thiol and amino groups on the AC supports. However, significant dehalogenation in the reaction mixture and Pd leaching from the heterogeneous catalysts were observed in continuous-flow mode.This unique phenomenon in continuous-flow mode resulted in a dramatic decline in reaction selectivity and durability of heterogeneous catalysts comparing with that of batch mode. In addition, the heterogeneous Pd catalysts with thiol-and amino-modified AC supports exhibited different reactivity and durability in batch and continuous-flow mode owing to the difference of interaction between Pd species and AC supports.

Nanoconfinement-induced water molecules and hydrogen molecules transport behaviors in ball-in-ball structure photocatalysts to improve hydrogen evolution

The diffusion,adsorption/desorption behaviors of water molecules and hydrogen molecules are of great importance in heterogeneous photocatalytic hydrogen production.In the study of structure-property-performance relationships,nanoconfined space provides an ideal platform to promote mass diffusion and transfer due to their extraordinary properties that are different from the bulk systems.Herein,we designed and prepared a nanoconfined CdS@SiO_(2)-NH_(2) nanoreactor,whose shell is composed of amino-functionalized silica nanochannels,and encapsulates spherical CdS as a photocatalyst inside.Experimental and simulated results reveal that the amino-functionalized nanochannels promote water molecules’and hydrogen molecules’directional diffusion and transport.Water molecules are enriched in the nanocavity between the core and the shell,and promote the interfacial photocatalytic reaction.As a result,the maximized water enrichment and minimized hydrogen-occupied active sites enable photocatalyst with optimized mass transfer kinetics and localization electron distribution on the CdS surface,leading to superior hydrogen production performance with activity as high as 37.1 mmol·g^(-1)·h^(-1).

Palladium nanoflowers supported on amino-fullerene as novel catalyst for reduction of 4-nitrophenol

In this study,we report the synthesis of novel palladium nanoflowers(Pd NFs)on amino-functionalized fullerene(C60-NH2)by hydrothermal self-assembly growth using ethylenediamine(EA)as a functional reagent.The successful formation of Pd nanoflowers supported amino-functionalized fullerene(C60-NH2/Pd NFs)is evidenced by UV-vis and powder X-ray diffraction(XRD).The morphology of Pd NFs over the C60-NH2 surface has been investigated by high-resolution transmission electron microscopy(TEM)and Fourier-transform infrared(FT-IR)techniques.The supported Pd nanoflowers(Pd NFs/C60-NH2)exhibit remarkably superior catalytic activity toward the reduction of 4-nitrophenol(4-NP).It exhibits remarkable UV-vis spectra response from 4-nitrophenol to 4-aminophenol(4-AP)(99%in 2.0 min)with a turnover frequency of 12.35 min^-1.Its excellent catalytic stability and durability offer the promising application in catalysis.