Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 11 de 11
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
J Colloid Interface Sci ; 566: 171-182, 2020 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-32004957

RESUMO

For the first time, herein this work, we have developed an effective and adaptable method to introduce defects onto the polymeric carbon nitride by simply grinding urea with urea nitrate which resulting new carbon nitride composite (UNU-C3N4) and melamine with urea nitrate which resulting new carbon nitride composite (UNM-C3N4). The UNU-C3N4 reveals high performance towards photocatalytic hydrogen production and as well as photocatalytic removal of contaminants. The results confirm that the defects enhanced the specific surface area, and improved performance of adsorbed oxygen which beneficial to generate more active radicals and more conducive sties to improve d the overall photocatalytic performance. The high N, H, and O content-enhanced electron polarization effects, by introducing the additional N, H, and O atoms into the g-C3N4 matrix, which will increase the charge transfer rate and charge separation efficiency. At the same time, the results of ESR also expression that the new type of as-prepared carbon nitride samples exhibit abundant of hydrogen radical (H) formation, which is also assist to improve the photocatalytic hydrogen production performance. As expected, the H2 evolution rate of UNU-C3N4(or UNM-C3N4) underneath simulated solar light irradiation is 9.93 times (13.76 times) than that of U-C3N4 (urea as raw material) (or M-C3N4 (melamine as raw material)). The high hydrogen evolution rates of UNU-C3N4 and UNM-C3N4 are 830.94 and 556.79 µmol g-1  h-1 under the visible-light irradiation, respectively. Meanwhile, the synthesized UNU-C3N4 and UNM-C3N4 material are demonstrated an efficient ability to degrade pollutants. In general, this work provides a viable way to introduce defects and hydrogen bands into the structure of carbon nitride.

2.
J Hazard Mater ; 391: 122183, 2020 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-32036308

RESUMO

Metal-free catalysts have been proved to be a low-cost and environmentally friendly species in aerobic oxidative desulfurization (ODS). In this work, exfoliated metal-free boron carbide with few-layered structure, small size, and abundant defects, was first employed in an aerobic ODS system for ultra-deep desulfurization. The exfoliation process was realized by employing a planetary ball mill strategy. Detailed characterizations showed that the ball milling process not only induces thinner layers and small sizes but also introduces numerous defects into the boron carbide catalysts, which is vital in metal-free catalysis. Furthermore, the exfoliated boron carbide catalyst was applied in aerobic ODS system, and 99.5 % of sulfur removal was obtained. Moreover, the catalyst can be recycled 17 times without a significant decrease in catalytic activity. In particular, it was found that ∼90 % of the sulfur compounds in real diesel oil could be removed by the current aerobic ODS system.

3.
ACS Appl Mater Interfaces ; 11(40): 36666-36675, 2019 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-31525889

RESUMO

Surface oxygen vacancy can greatly affect the properties of transition-metal oxides. However, engineering oxygen vacancy-abundant transition-metal oxides with high specific surface area (SSA) remains challenging. At present, the generation of oxygen vacancies in metal oxides is time-consuming and less environmentally friendly by chemical leaching methods that usually require additional waste treatment. Herein, a series of oxygen vacancy-abundant transition-metal oxides with high SSA are constructed via a lattice refining strategy. This strategy is realized by urea-assisted ball milling pyrolysis and is green, efficient, and universal. The oxygen vacancies promote the mobility of oxygen, leading to a boosted catalytic oxidation performance of aromatic sulfides. Such a strategy provides an efficient approach to manufacturing oxygen vacancies on transition-metal oxides, which may be beneficial for various related applications as an effective catalytic material.

4.
J Colloid Interface Sci ; 534: 239-247, 2019 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-30227380

RESUMO

Phosphomolybdate-based ionic liquid [(C8H17)3NCH3]3PMo12O40 was prepared and supported on a magnetic mesoporous silica (γ-Fe2O3@SiO2@mSiO2) to obtain a magnetic mesoporous catalyst. The morphology and components of the catalyst were characterized by FT-IR, XRD, XPS, SEM, TEM, nitrogen adsorption-desorption isotherms, and VSM. With air as oxidant, the catalyst showed perfect desulfurization performance in oxidation of dibenzothiophene (DBT). The removal of DBT from model oil could reach 100% within 5 h at 120 °C. After reaction, the catalyst could be separated by a magnet and recycled at least four times without obvious decrease in the catalytic performance.

5.
J Colloid Interface Sci ; 528: 70-81, 2018 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-29843064

RESUMO

ZnFe2O4/AgI composites were first prepared successfully with a hydrothermal method, and ZnFe2O4 nanoparticles were uniformly decorated on the surface of AgI particles. The photocatalytic activities of the obtained ZnFe2O4/AgI composites were investigated by the degradation of organic pollutants and the inactivation of bacteria under visible light irradiation. The results showed that the introduction of ZnFe2O4 greatly enhanced the light harvesting ability and improved the separation efficiency of the photogenerated charge carriers, which contributed to the enhanced generation of reactive species and thus promoted the photocatalytic performance. The 5% ZnFe2O4/AgI composite exhibited the optimal photocatalytic disinfection of E. coli (100% removal efficiency in 80 min) as well as the photocatalytic degradation of rhodamine B (RhB) (98.5% removal rate in 40 min). Furthermore, four consecutive cycles also demonstrated the stable photocatalytic activity of the as-prepared ZnFe2O4/AgI composites. In addition, H2O2 was identified as the predominant active species in the photocatalytic inactivation of bacteria. This study indicated that ZnFe2O4/AgI composites are a promising candidate for the treatment of wastewater.


Assuntos
Antibacterianos/química , Desinfecção/métodos , Compostos Férricos/química , Iodetos/química , Nanopartículas/química , Fotólise , Compostos de Prata/química , Zinco/química , Antibacterianos/síntese química , Antibacterianos/farmacologia , Catálise , Poluentes Ambientais/química , Poluentes Ambientais/isolamento & purificação , Recuperação e Remediação Ambiental/métodos , Escherichia coli/efeitos dos fármacos , Infecções por Escherichia coli/tratamento farmacológico , Compostos Férricos/síntese química , Compostos Férricos/farmacologia , Humanos , Iodetos/síntese química , Iodetos/farmacologia , Nanopartículas/ultraestrutura , Rodaminas/química , Rodaminas/isolamento & purificação , Compostos de Prata/síntese química , Compostos de Prata/farmacologia , Zinco/farmacologia
6.
J Colloid Interface Sci ; 508: 121-128, 2017 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-28822861

RESUMO

In this paper, the carbon-doped boron nitride nanoplate (C-BNNP) was prepared by pyrolyzing the precursor under N2 and served as an excellent adsorbent for removal of Rhodamine B (RhB). The structure and composition of C-BNNP were characterized and its adsorption behavior for RhB was investigated. Compared with boron nitride nanoplate (BNNP) which was synthesized under NH3, C-BNNP displayed an enhancement of the adsorption capacity for RhB (833mg/g). The adsorption activity was comprehensibly studied by kinetics, isotherm and thermodynamics. The adsorption kinetics followed pseudo-second-order model. The equilibrium adsorption data agreed well with the Langmuir isotherm. And the thermodynamics indicated that the adsorption process was a spontaneous, exothermic and physisorption process. In addition, the density functional theory was proposed that doping carbon in the BNNP decreased the chemical hardness of the adsorbent and enhanced the adsorption capacity of C-BNNP for RhB.

7.
Dalton Trans ; 44(25): 11582-91, 2015 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-26040758

RESUMO

The low photocatalytic activity of single semiconductor photocatalysts mainly originates from their fast recombination of photogenerated electron-hole pairs. Constructing nanosheet-based composite photocatalysts is an effective way to enhance the charge separation efficiency of photogenerated electron-hole pairs. In this work, AgI-decorated ß-Bi2O3 nanosheet heterostructured photocatalysts were prepared by a facile method. The as-obtained AgI/ß-Bi2O3 heterostructures exhibited enhanced visible-light-driven photocatalytic activity towards the degradation of methyl orange (MO) and tetracycline hydrochloride (TC) in aqueous solution. The optimum photocatalytic activity of 20%-AgI/ß-Bi2O3 for the degradation of MO was about 4.1 and 6.2 times higher than that of AgI and ß-Bi2O3. The photocatalytic activity enhancement of AgI/ß-Bi2O3 heterostructures could be ascribed to the formation of a Z-scheme system, which results in the efficient space separation of photo-induced charge carriers.

8.
Dalton Trans ; 43(41): 15429-38, 2014 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-25190481

RESUMO

Novel sphere-like MoS2/BiOBr composites were prepared by a facile ethylene glycol (EG)-assisted solvothermal process in the presence of the ionic liquid 1-hexadecyl-3-methylimidazolium bromide ([C16mim]Br). A nanostructured heterojunction, with few-layer MoS2 deposited on the surface of BiOBr microspheres, was constructed. During the synthetic process, the ionic liquid acted as a reactant, a template and a dispersing agent at the same time, leading to the formation of few-layer MoS2 dispersed on the surface of BiOBr microspheres. The MoS2/BiOBr composites exhibited much higher visible light photocatalytic activity towards rhodamine B (RhB) photodegradation than pure BiOBr. 3 wt% MoS2/BiOBr possessed the optimal photocatalytic activity, which was approximately 2.5 times as high as that of pure BiOBr. Through multiple characterization techniques, the relationship between the specific structure and the admirable photocatalytic activity of the MoS2/BiOBr microspheres was investigated. The critical role of the few-layer MoS2 in the MoS2/BiOBr microspheres was explored. A photocatalytic mechanism for the MoS2/BiOBr composites was also proposed.

9.
Chemistry ; 20(8): 2244-53, 2014 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-24458597

RESUMO

A liquid/liquid interfacial reaction system was designed to fabricate α-Fe2O3 cubes. The reaction system uses a hydrophobic ionic liquid containing iron ions ([(C8H17)2(CH3)2N]FeCl4) for manufacturing α-Fe2O3 cubes by a novel and environmentally friendly hydrothermal method under low-temperature conditions (140 °C). The iron-containing ionic liquid is hydrophobic and can form a liquid/liquid interface with water, which is vital for fabrication of the α-Fe2O3 cubes. Nanomaterials synthesized from hydrophobic iron-containing ionic liquids show good crystallinity, well-developed morphology, and uniform size. The effect of different ionic liquids on the morphology of α-Fe2 O3 was investigated in detail. [(C8H17)2(CH3)2N]FeCl4 is assumed to perform the triple role of forming a liquid/liquid interface with water and acting as reactant and template at the same time. The effect of the reaction temperature on the formation of the α-Fe2O3 cubes was also studied. Temperatures lower or higher than 140 °C are not conducive to formation of the α-Fe2O3 cubes. Their photoelectrochemical properties were tested by means of the transient photocurrent response of electrodes modified with as-prepared α-Fe2O3 cubes. The photocurrent response of an α-Fe2O3 cubes/indium tin oxide electrode is high and stable, and it shows great promise as a photoelectrochemical glucose sensor with high sensitivity and fast response, which are beneficial to practical applications of nanosensors.

10.
Dalton Trans ; 42(18): 6468-77, 2013 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-23471128

RESUMO

α-Fe2O3 hollow microspheres have been successfully prepared in the presence of metal ion-containing reactable ionic liquid 1-octyl-3-methylimidazolium tetrachlorideferrate(III) ([Omim]FeCl4) under the solvothermal condition. The as-prepared samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), FT-IR spectrum, and diffuse reflectance spectroscopy (DRS). The effect of concentration of ionic liquids on the morphology of α-Fe2O3 had been investigated in detail. It was found that [Omim]FeCl4 acted not only as Fe source but also as solvent and template for the fabrication of α-Fe2O3 hollow microspheres. In addition, the electrochemical and photocatalytic properties of α-Fe2O3 were investigated. The α-Fe2O3 hollow microspheres exhibited high conductivity, high photocurrent, and high photocatalytic activity. The designed hollow microsphere showed potential applications in photocatalysis.

11.
Guang Pu Xue Yu Guang Pu Fen Xi ; 22(4): 648-50, 2002 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-12938388

RESUMO

Reaction of Ni[(C4H9O)2PS2]2 with ethylamine, n-propylamine, n-butylamine, and n-amylamine have been studied by spectrophotometry in ethanol at 30 degrees C. For nitrogen base(B), the adduct formation of NiL2.B and NiL2.B2 is established, and their additive equilibrium constants (lg beta n) and molecular number (n) have been discussed. All the NiL2.B and NiL2.B2 complexes exhibit virtually the same electronic spectra arising from the five-coordinate NiNS4 and six-coordinate NiN2S4 chromophore respectively. The constants (lg beta n) increase with basicity (pKa) of nitrogen base and can be described by experimental formulas: lg beta 1 = -9.69 +1.15 pKa; lg beta 2 = -18.73 +2.28 pKa.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA