DALTON TRANSACTIONS
·
2021
·Vol. 50
·期 45
·16795-16802
·
IF 4.39
Su-Yun Zhang,Fangchao Long,Chenxu Kang,Zhengyuan Jin,Ailun Zhao,Huawei Liang,Shuangchen Ruan,Yu-Jia Zeng
γ-phase copper(I) iodide (abbreviated to CuI hereafter) with different morphologies is realized through a one-step redox process from I-containing ionic liquid (IL) or poly(ionic liquid)s (PILs) precursors at room temperature. The phase composition, morphology, and electronic states of the synthesized CuI samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The resulting CuI products exhibit three different types of morphologies, namely nanocrystals, with an average size of 0.8 ± 0.2 μm, nanoplates, with a thickness of 35.8 ± 0.9 nm, and nanoflowers, with petals with a thickness of 12.2 ± 0.8 nm. Moreover, the as-synthesized CuI samples exhibit gradually diminishing bandgaps and improved photocatalysis performance for the photodegradation of rhodamine B (RhB) under visible light irradiation as the thickness decreases. XPS measurements confirm that IL/PILs coupled to the CuI surface, resulting in a further charge transfer between Cu and I. These results conclusively prove that IL/PILs serve as both the reducing agents and assemble as orientation templates in the formation of the CuI nanostructures, and also successfully mediate the functional properties of the samples by changing the surface electronic structures.
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高影响因子
ENERGY CONVERSION AND MANAGEMENT
·
2019
·
IF 7.181
Yujiao Zhang,Shengli Niu,Chunmei Lu,Zhiqiang Gong,Xun Hu
This research focused on the novel, low-cost and green NaAlO 2 /γ-Al 2 O 3 heterogeneous nanocatalyst, which exhibited the excellent performance in catalyzing transesterification of palm oil with methanol for the biodiesel production. The physicochemical properties of the catalysts were characterized by different methods of the X-ray diffraction (XRD), N 2 adsorption–desorption, attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), Hammett indicators, field emission scanning electron microscopy-energy dispersive spectrometer (FESEM-EDS) and inductively coupled plasma-optical emission spectrometry (ICP-OES). The transesterification parameters, such as the methanol to oil molar ratio, catalyst content and reaction temperature, were optimized using the central composite design (CCD) based the response surface methodology (RSM), where the maximum biodiesel yield of 97.65% was achieved at the methanol to oil molar ratio of 20.79:1, catalyst content of 10.89 wt% and reaction temperature of 64.72 °C. The biodiesel yield was dropped to 52.16% for the third reused cycle due to the leaching of the active sites into the liquid phase. However, the spent catalyst could be effectively regenerated with a small number of active sites and the regenerated catalyst maintained the biodiesel yield of 93.29% for the sixth reused cycle. The properties of the produced biodiesel were in accordance with the ASTM D 6751 standard. Also, the biodiesel production process was environmental friendly based on the green chemistry metrics.
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Catalysts
·
2019
·Vol. 9
·期 10
·849
·
IF 3.444
Zeyu Xue,Zhaoping Zhong,Bo Zhang,Chao Xu
To investigate the catalytic pyrolysis performance of complex metal oxide catalysts for biomass, γ-Al2O3was prepared through the precipitation method, and then ZrO2and γ-Al2O3were blended in the proportion of 2:8 using the co-precipitation method. Next, CeO2was loaded on the surface of the catalyst for further modification. The three catalysts, A, ZA and CZA, were obtained. The specific surface and acidity of the catalysts were characterized by nitrogen adsorption–desorption and NH3-Temperature Programmed Desorption (NH3-TPD) respectively. The catalytic pyrolysis performance of catalysts for bamboo residues was investigated by Pyrolysis gas chromatography mass spectrometry (Py-GC/MS). Chromatograms were analyzed for identification of the pyrolysis products and the relative amounts of each component were calculated. Experimental results indicated that catalyst A had a good catalytic activity for the fast pyrolysis of bamboo residues. The addition of ZrO2and CeO2could continuously enhance the acidity of the catalyst and further promote the pyrolysis of macromolecular compounds and deoxidation of oxygen-containing compounds. Finally, catalyst CZA, obtained by compound modification, could not only dramatically reduce the relative content of phenol, acid and aldehyde and other oxygen-containing compounds, but also achieved the maximum hydrocarbon yield of 23.38%. The catalytic performance of catalyst CZA improved significantly compared with catalyst A.Keywords:biomass;pyrolysis;catalytic cracking;Py-GC/MS;complex metal oxides
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RSC Advances
·
2019
·Vol. 9
·期 19
·10702-10714
·
IF 3.049
Cunlong Li,Yuqing Zhang,Ming Yong,Wei Liu,Jiaqi Wang
In order to effectively clean oily seawater with anionic polyacrylamide (APAM), UiO-66 coated γ-Al2O3 (UA) composites were firstly synthesized using γ-Al2O3 as a template to induce the growth of high hydrophilic UiO-66 on its surface to form a uniform UA self-assembled membrane. The UA composites and self-assembled membrane were characterized and analyzed. Also, the membrane performance was investigated. The results show that the hydrophilicity of particles is enhanced with the water contact angle decreasing from 39.8° (γ-Al2O3 particles) to 26.2° (UA composites) by introducing the UiO-66 coating. Moreover, the UA self-assembled membrane performs attractive water yield and separation performance. The oil concentration in the permeate treated by the first class of UA self-assembled membrane declines apparently from 91.22 to 18.90 mg L−1, while the water yield is as high as 657.89 L m−2 h−1. The reclaimed separation experiments show that the membrane materials could be recycled by calcination at 200 °C and hydraulic cleaning, which gives the material potential application in cleaning oily seawater.
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NEW JOURNAL OF CHEMISTRY
·
2019
·Vol. 43
·期 35
·13891-13898
·
IF 3.069
Fenfen Lu,Daohua Sun,Xia Jiang
In this dissertation, silver–palladium (AgPd) bimetallic nanoparticles were synthesized by a green biosynthesis method using Cacumen platycladi leaf extract, which provided both reductive and protective agents. Then the supported AgPd/γ-Al2O3 catalysts were obtained by the sol-immobilization method, and the as-biosynthesized AgPd/γ-Al2O3 catalysts with different particle sizes and compositions were used for 1,3-butadiene hydrogenation. Optimization of the catalyst preparation and selective hydrogenation parameters was performed. Using the catalyst, a 1,3-butadiene conversion of 98.2% and a butene selectivity of 88.1% were achieved. The durability experiment of AgPd/γ-Al2O3 catalysts was carried out for 50 h, and the activity decreased slightly and the selectivity almost remains the same during the 50 h, indicating their remarkable stability. The results of TEM and TG analysis showed that the size of the AgPd nanoparticles was nearly the same before and after the durability experiment, and the existence of residual biomolecules on the catalyst surface helped to prevent agglomeration and modification of the surface properties of the catalyst, which would promote desorption of the product, and then avoid intensifying the level of further hydrogenation.
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CARBOHYDRATE POLYMERS
·
2019
·
IF 6.044
Zongrui Tong,Jueying Yang,Lizhi Lin,Ruiqi Wang,Bin Cheng,Yu Chen,Liansheng Tang,Jianying Chen,Xilan Ma
In the present work, a poly(γ-glutamic acid)/alginate/silver nanoparticle (PGA/Alg/AgNP) composite microsphere with excellent antibacterial and hemostatic properties was prepared by the in situ UV reduction and emulsion internal gelation method, and its potential application for antibacterial hemostatic dressing was explored. Well dispersed AgNPs were in situ synthesized by a UV reduction method with alginate as stabilizer and reductant. The AgNPs showed excellent antibacterial activities against both gram-negative and gram-positive bacteria. Additionally, the AgNPs prepared by the in-situ UV reduction exhibited better biocompatibility and antibacterial effects than those prepared by the conventional chemical reduction method. PGA/Alg/AgNP composite microspheres were then prepared with the AgNPs by an emulsion internal gelation method. Such microspheres were found to be a porous and hollow network with pH-sensitive swelling properties and excellent hemostatic performance, indicating its application potentials as an advanced antibacterial hemostatic material.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2019
·
IF 3.375
Fuhang Mai,Zhe Wen,Yunfei Bai,Zewei Ma,Kai Cui,Kai Wu,Fei Yan,Hong Chen,Yongdan Li
A WO3/γ-Al2O3 catalyst prepared by an incipient-wetness impregnation method is employed in the selective conversion of enzymatic hydrolysis lignin (EHL) into various alkylphenols in supercritical ethanol. In the reaction, EHL is completely dissolved and converted into aliphatic and aromatic compounds with a total yield of 363.4 mg/g lignin at 320 °C for 8 h. The yield of aromatic compounds is 315.8 mg/g lignin, accounting for 86.9% of the total yield of the products, and the overall selectivity of alkylphenols reaches 67.5%. Compared to WO3 and H2WO4, the WO3/γ-Al2O3 shows a higher activity for the conversion of EHL in supercritical ethanol. Besides, ethanol is found to be the most effective solvent for the depolymerization of EHL with the WO3/γ-Al2O3 catalyst. The WO3/γ-Al2O3 keeps the high catalytic activity in three reuses.
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JOURNAL OF THE CHINESE CHEMICAL SOCIETY
·
2018
·Vol. 65
·期 11
·1398-1406
·
IF 0.862
Ruiying Wang,Jianjia Wang,Huimin Zi,Haijun Wang,Yongmei Xia,Xiang Liu
Three novel heterogeneous Zr-containing organic–inorganic hybrid catalysts were prepared for the transfer hydrogenation of biomass-derived ethyl levulinate (EL) to γ-valerolactone (GVL) with isopropyl alcohol (IPA) as the hydrogen donor and were characterized by Fourier transform infrared (FT-IR), Temperature-programmed desorption (TPD), Thermogravimetry (TG), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). On their basis, the effects of temperature, time, the amount of catalyst, and the solvent were investigated on the yield of GVL. A GVL yield of 96.5% with 99% EL conversion was obtained using Zr-Pg, which was prepared by the reaction of ZrCl 4 and phloroglucinol (Pg) in N , N -dimethylformamide (DMF) at room temperature. The high catalytic activity may be attributed to the strong basicity, which was increased by the sufficient quantity of phenate in the structure of Zr-Pg. Meanwhile, Zr-Pg could be efficiently and easily recycled at least five times without any notable loss of activity and selectivity. Through the results of comparative experiments and characterization, we propose a plausible reaction mechanism for the high activity of Zr-Pg.
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CATALYSIS LETTERS
·
2018
·Vol. 148
·期 11
·3402-3412
·
IF 2.911
Bao Qiang,Qi Hui,Zhang Chunlei,Ning Chunli,Zhang Yi,Jiang Ye,Wu Yifan,Gui Wenying,Wang Zhenlu
Abstract In this work, titanium-doped mesoporous Al 2 O 3 (γ-Ti–Al 2 O 3 ) was prepared by an evaporation-induced self-assembly method and used as a carrier of Ba/γ-Ti–Al 2 O 3 catalyst to catalyze the aldol condensation of methyl acetate with formaldehyde to methyl acrylate in a fixed-bed reactor. The catalysts were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, N 2 adsorption–desorption, pyridine absorption performed via Fourier transform infrared spectroscope (Py-IR), and NH 3 and CO 2 temperature-programmed desorption (NH 3 and CO 2 -TPD). Experimental results indicated that the doping of the titanium species into the frame work of mesoporous Al 2 O 3 (γ-Ti–Al 2 O 3 ) had a significant influence on the catalytic activity via modifying the acid–base surface properties of the catalyst. Furthermore, the Ba/γ-Ti–Al 2 O 3 catalyst demonstrated excellent catalytic performance, with a methyl acetate conversion rate of 50% and methyl acrylate selectivity up to 90.2%. Compared with the Ba/Al 2 O 3 catalyst, the Ba/γ-Ti–Al 2 O 3 catalyst had better catalytic activity, stability and potential for practical application, which was likely due to an increased number of Lewis acid sites, especially the medium acid sites. Graphical Abstract Barium supported mesoporous γ-Ti–Al 2 O 3 catalyst was found to be an effective catalyst for vapor phase aldol condensation of methyl acetate with formaldehyde.
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Materials
·
2018
·Vol. 11
·期 9
·1505
·
IF 2.467
Yan Song,Xu Zong,Nan Wang,Ning Yan,Xueying Shan,Jinchun Li
Lignin can be a candidate as a charring agent applied in halogen-free flame retardant polymers, and incorporation of silicon and nitrogen elements in lignin can benefit to enhancing its thermal stability and charring ability. In the present work, wheat straw alkali lignin (Lig) was modified to incorporate silicon and nitrogen elements by γ-divinyl-3-aminopropyltriethoxysilane, and the modified lignin (CLig) was combined with ammonium polyphosphate (APP) as intumescent flame retardant to be applied in poly(Lactic acid) (PLA). The flame retardancy, combustion behavior and thermal stability of PLA composites were studied by the limited oxygen index (LOI), vertical burning testing (UL-94), cone calorimetry testing (CCT) and thermogravimetric analysis (TGA), respectively. The results showed a significant synergistic effect between CLig and APP in flame retarded PLA (PLA/APP/CLig) occured, and the PLA/APP/CLig had better flame retardancy. CCT data analysis revealed that CLig and APP largely reduced the peak heat release rate (PHRR) and total heat release rate (THR) of PLA, indicating their effectiveness in decreasing the combustion of PLA. TGA results exhibited that APP and CLig improved the thermal stability of PLA at high temperature. The analysis of morphology and structure of residual char indicated that a continuous, compact and intumescent char layer on the material surface formed during firing, and had higher graphitization degree. Mechanical properties data showed that PLA/APP/CLig had higher tensile strength as well as elongation at break.Keywords:wheat straw soda lignin;silicon and nitrogen elements;poly(lactic acid);thermal stability;combustion behavior
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ACS Catalysis
·
2015
·
IF 9.312
Kunfeng Zhao,Hailian Tang,Botao Qiao,Lin Li,Junhu Wang
Au/γ-Fe2O3 and Au/α-Fe2O3 catalysts with identical size of Au nanoparticles, chemical state of Au species, and amount of surface OH– group were prepared. The Au/γ-Fe2O3 catalyst exhibited exceptionally high activity, regardless of the heat treatments. The CO-TPR, sequential pulse reaction, and in situ Raman spectra demonstrate that the much higher activity of Au/γ-Fe2O3 originated from its higher redox property at low temperature. Systematic study shows that this higher-redox-property-based higher activity could be extended to γ-Fe2O3-supported Pt-group metals and to other reactions that follow Mars–Van Krevelen mechanism. This finding may provide a new avenue for catalyst improvement or development by choosing the suitable crystal phase of the oxide support.
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ACS Sustainable Chemistry & Engineering
·
2015
·
IF 4.642
Hu Li,Zhen Fang,Song Yang
Acid–base bifunctional superparamagnetic FeZrOx nanoparticles were synthesized via a two-step process of solvothermal treatment and hydrolysis–condensation, and were further employed to catalyze the conversion of ethyl levulinate (EL) to γ-valerolactone (GVL) using ethanol as both H-donor and solvent. ZrFeO(1:3)-300 nanoparticles (12.7 nm) with Fe3O4 core covered by ZrO2 layer (0.65 nm thickness) having well-distributed acid–base sites (0.39 vs 0.28 mmol/g), moderate surface area (181 m2/g), pore size (9.8 nm), and strong magnetism (35.4 Am2 kg–1) exhibited superior catalytic performance, giving a high GVL yield of 87.2% at 230 °C in 3 h. The combination of the nanoparticles with solid acid HY2.6 promoted the direct transformation of sugars to produce GVL in moderate yield (around 45%). Moreover, the nanocatalyst was easily recovered by a magnet for six cycles with an average GVL yield of 83.9% from EL.
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