NANO
·
2018
·
IF 1.1
Yunlei Zhang,Pei Jin,Minjia Meng,Lin Gao,Meng Liu,Yongsheng Yan
The direct synthesis of metal-organic frameworks (MOFs) with acidic and basic active sites is challenging due to the introduction of functional groups by post-functionalization method often jeopardize the framework integrity. Herein, we report the direct synthesis of acid-base bi-functional MOFs with tuning acid-base strength. Employing modulated hydrothermal (MHT) approach, microporous MOFs named UiO-66-NH 2 was prepared. Through the ring-opening reaction of 1,3-propanesultone with amino group, UiO-66-NH 2 -SO 3 H-type catalysts can be obtained. The synthesized catalysts were well characterized and their catalytic performances were evaluated in one-pot glucose to 5-HMF conversion. Results revealed the acid-base bi-functional catalyst possessed high activity and excellent stability. This work provides a general and economically viable approach for the large-scale synthesis of acid-base bi-functional MOFs for their potential use in catalysis field.
研究领域:
催化化学
·
材料科学
✓ 已验证
DOI
高影响因子
ADVANCED ENGINEERING MATERIALS
·
2020
·Vol. 22
·期 8
·2000267
·
IF 3.217
Hao Zou,Yi Zhou,Ye Xiang,Yuehong Deng,Yawen Tan,Haiqin Tang,Yifeng Xu
The formation of heterojunctions is an effective method to develop visible light-driven photocatalytic materials. A flower-like DUT-5@BiOBr composite is prepared by the hydrothermal method. The presence of a large number of heterojunctions in the 2D–2D interface accelerates the separation of photogenerated charges. When the mass ratio is 20%, the composite material shows the highest visible light catalysis and excellent stability in cycling experiments. The photocatalytic mechanism is analyzed by various characterization methods. The results show that the main active species in the photocatalytic process are superoxide radicals and holes and prove that the heterojunction that forms between DUT-5 and BiOBr is a type-II heterojunction. The synergy between the increase in specific surface area, the unique mesoporous structure, and the heterojunction promotes the speed of photocatalysis. Herein, new ideas are provided for the development of 2D–2D composite materials to degrade organic pollutants under visible light to solve environmental pollution.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
ENERGY & FUELS
·
2022
·
IF 4.654
Jun Zhang,Zhen Wu,Yafei Wu,Xiaoling Liu,Xun Li,Yu Zhang,Haian Xia,Fei Wang
Catalytic cracking of fatty acid methyl esters (biodiesel) is an attractive alternative to petroleum processing to produce valuable and versatile aromatics over the Zn-modified HZSM-5(25) catalysts. The catalysts with a Zn loading amount of 0–2.6 wt % were prepared and characterized. The introduction of Zn species presented great effects on the textural property and acidity of the parent HZSM-5(25) zeolite, and the chemical state of Zn species was heavily dependent on the amount of Zn loading. The strong Brönsted acid sites on the 0.5% Zn/HZSM-5(25) catalyst were exchanged by Zn species and formed new Zn-Lewis acid sites, which were identified as [ZnOH]+ and Zn2+ species. These Zn species greatly enhanced the dehydrogenation activation of alkanes to form more alkenes. Besides, they also promoted the further dehydrogenation reactions during aromatization of alkenes, thus improving the formation of H2 (>4 wt %) and increasing the production of aromatics (>40 wt %). The dominant components in the organic liquid product were monocyclic aromatics including benzene, toluene, and xylenes. Moreover, the 0.5% Zn/HZSM-5(25) catalyst exhibited an excellent stability, adaptability, and regeneration.
研究领域:
化学工程
·
催化科学
✓ 已验证
DOI
高影响因子
JOURNAL OF THE ENERGY INSTITUTE
·
2019
·
IF 3.774
Xiaohua Li,Wenbin Dong,Jin Zhang,Shanshan Shao,Yixi Cai
The Fe-, Co-, Cu-loaded HZSM-5 zeolites were prepared via impregnation method. The upgrading by catalyst on biomass pyrolysis vapors was conducted over modified zeolites to investigate their catalytic upgrading performance and anti-coking performance. The Brønsted acid sites amount on Cu-,Co-loaded HZSM-5 decreased sharply, while that of Lewis both increased. The yield of liquid fraction and refined bio-oil over metal loaded ZSM-5 catalysts decreased, while that of char almost kept constant. The physical property of refined bio-oil was promoted in terms of pH value, dynamic viscosity and higher heating value (HHV). FT-IR analysis revealed that the chemical structure of refined bio-oil obtained over Fe-, Co-, Cu-loaded HZSM-5 zeolites was highly similar. The yield of monocyclic aromatic and aliphatic hydrocarbon over Fe-,Co-loaded HZSM-5 were boosted by around 2.5 times compared with original ZSM-5 zeolites. Data analysis revealed that Cu/HZSM-5 presented the worst deoxygenation ability. The anti-coking capability of Fe/HZSM-5 was obviously better, i.e., the coke content showed an approximate decrease of 38%. Thus, this study provided an efficient Fe/HZSM-5 catalysts for preparation of bio-oil derived from catalytic upgrading of biomass pyrolysis vapor.
研究领域:
能源与燃料
·
催化化学
✓ 已验证
DOI
高影响因子
Scientific Reports
·
2017
·Vol. 7
·期 1
·1-9
·
IF 4.259
Wang Chao,Zhang Liming,Zhou Tian,Chen Jiachuan,Xu Feng
5-hydroxymethylfurfural (HMF) is an important platform molecule in the synthesis of various chemicals and materials. Herein, we reported a simple and effective dehydration of glucose-based carbohydrates to HMF in a biphasic system containing cyclopentyl methyl ether as the organic phase and AlCl 3 with minute amounts of HCl as co-catalysts. The results showed that the mixed catalysts had a positive synergistic catalytic effect on glucose conversion to HMF compared with single AlCl 3 or HCl catalyst. For glucose, the highest HMF yield of 54.5% was achieved at 175 °C for 20 min. More importantly, the optimal catalytic system was so efficient that it achieved one of the highest reported yields of HMF (30.5%) directly from corncob acid hydrolysis residues. Thus, the catalytic system can become a promising route for effective utilization of biomass in future biorefineries.
研究领域:
生物化学
·
催化化学
✓ 已验证
DOI
PubMed
高影响因子
Reaction Kinetics Mechanisms and Catalysis
·
2018
·Vol. 124
·期 2
·587-601
·
IF 1.515
Wang Tao,Zhang Xinyu,Liu Jun,Liu Hanzi,Sun Baomin
NO conversion using dielectric barrier discharge (DBD) plasma with different catalysts was investigated. Cu/TiO 2 , Cu/Al 2 O 3 , Cu/ZSM-5, Cu/CNTs and Cu/AC catalysts were prepared by incipient wetness impregnation with 4 wt% Cu loaded. BET, SEM, XRD, XPS, H 2 -TPR, NH 3 -TPD were used to measure and evaluate various catalysts. Compared with the plasma only process, the combination of plasma with different catalysts significant improved the NO conversion rate. The highest NO conversion rate of 76% could be achieved with Cu/ZSM-5 catalyst at the energy density of 184 J/L. The results indicate that Cu species over the support ZSM-5 can produce high concentrations of CuO, largest specific surface area, largest amounts of acidity and lowest reduction temperature (209 °C), these factors conducive to plasma-catalyst reaction. Besides, Cu/TiO 2 and Cu/Al 2 O 3 catalysts exhibited excellent NO conversion at the low energy density because of the low thermal stability. After plasma-catalyst reaction, the reducibility of CuO and Cu 2 O over supports decreased and the peak position of acid sites shifted to lower temperature.
研究领域:
环境科学
·
催化化学
✓ 已验证
DOI
高影响因子
Molecular Catalysis
·
2017
·
IF 0
Shuang Chu,Li’na Yang,Xingcui Guo,Linlin Dong,Xiufang Chen,Yaru Li,Xindong Mu
The catalytic behavior of a series of MFI catalysts with different Si/Al ratio (25–300) in the direct aqueous-phase hydrolysis of α-cellulose was studied. The effects ultrasonic pretreatment time, ZnCl 2 content, zeolite pore structure and acid-basic properties on catalyst activity and products distribution were systematically investigated. The results indicated that HZSM-5 with lower Si/Al ratio was beneficial for production of glucose and LA from α-cellulose. Ultrasonic pretreatment could decrease the degree of crystallinity and polymerization of α-cellulose, enhance the accessibility of acid sites and ZnCl 2 to the loosened amorphous regions of α-cellulose in water, and improve the hydrolysis efficiency of α-cellulose. The desilicated ZSM-5 (HZSM-5-DS(0.2)) showed much higher catalytic activities as compared to commercial ZSM-5 and α-cellulose conversion reached 76.5% over HZSM-5-DS(0.2) at 200 °C. Catalytic conversion of α-cellulose consisted of at least three important parallel reactions under the present hydrothermal conditions and a plausible pathway was proposed. Effective control of these reactions would be helpful to further maximize the target product yield during the catalytic conversion of α-cellulose.
研究领域:
化学工程
·
生物质转化
✓ 已验证
DOI
Catalysis Science & Technology
·
2016
·Vol. 6
·期 8
·2647-2652
·
IF 5.287
Hualei Hu,Jinghui Lyu,Jiayao Rui,Jie Cen,Qunfeng Zhang,Qingtao Wang,Wenwen Han,Xiaonian Li
Ethylbenzene is the major side product in benzene alkylation with methanol and it is difficult to be suppressed over hierarchical porous ZSM-5. Moreover, the separation of ethylbenzene from xylene still remains a great challenge. Our research indicated that ethylbenzene formation could be highly suppressed by changing the Si/Al ratio of the catalyst. Hierarchical porous ZSM-5 catalysts with different Si/Al ratios were prepared via reducing the amount of Al in the solvent evaporation assisted dry gel conversion method. In this method, tetra-n-propylammonium hydroxide was used as the direct agent to create micropores, and hexadecyltrimethoxysilane was added to create additional porosities by forming organic assemblies which occupied a certain space between zeolitic walls. The catalyst with a Si/Al ratio of 1800 could achieve high benzene conversion (59.5%) and high xylene selectivity (39.0%) as well as excellent suppression of ethylbenzene formation (<0.1%).
研究领域:
催化化学
·
材料科学
✓ 已验证
DOI
高影响因子
RSC Advances
·
2015
·Vol. 5
·期 43
·33809-33813
·
IF 3.84
Bo Xiao,Ying Fan,Rui-han Gao,Peng Chen,Jian-xin Zhang,Qing-di Zhou,Sai-Feng Xue,Qian-Jiang Zhu,Zhu Tao
A one-pot strategy was employed to synthesize a series of cucurbit[5]uril-anchored (Q[5]-anchored) polymers with high yields. The acrylic acid (AA) monomer, an ammonium persulfate salt (APS) initiator, and an oxidant were used in the polymerization. The Q[5]-anchored polyacrylic acid aggregates (Q[5]-PAA) have been characterized by 1H NMR, 13C NMR, 2D NMR, FTIR, TGA, GPC, TEM and SEM measurements. The experimental results confirm that PAA chains can be grafted to Q[5] in a controlled manner through an in situ radical polymerization approach. The effects of acrylic acid and Q[5] feed mass and APS concentration on the formation of polymer nanocapsules have been investigated. The experiments reveal that the feed mass of acrylic acid greatly influences the properties of Q[5]-PAA when the ratio of Q[5]/APS is fixed at 0.5. In particular, when APS/Q[5] = 46 and 72, vesicle structures are observed in the Q[5]-anchored polymers. Moreover, such polymer nanocapsules show selective absorption of some volatile compounds, particularly methanol.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
Applications in Energy and Combustion Science
·
2021
·
IF 0
Huiyan Zhang,Bingbing Luo,Kai Wu,Han Wu,Jiajun Yu,Siyu Wang
Catalytic fast pyrolysis of lignin is easy to cause agglomeration and coking, resulting in low-yield aromatic hydrocarbons. Catalytic pyrolysis of modified lignin combined with metal-modified HZSM-5 was proposed to enhance the aromatic yield. The experiment results showed that chemical modification with Ca(OH) 2 not only inhibited the agglomeration behavior of lignin but also increased the yield of light phenolic compounds. Moreover, Ca 2+ -loaded lignin combined with metal-modified HZSM-5 was conducive to the formation of aromatics. The total yield of aromatics from the catalytic fast pyrolysis of Ca 2+ -loaded lignin over Zn/HZSM-5 was improved from 31.1 to 46.1 mg/g. The mechanism insight showed that Ca 2+ modification realized the chemical combination between Ca 2+ and the functional groups which are responsible for the agglomeration of lignin, and then the introduction of the Zn species suppressed the hydrogen transfer reaction and enhanced the dehydrogenation pathway, resulting in the increase of aromatic yield.
研究领域:
化学工程
·
能源科学
·
材料科学
✓ 已验证
DOI
Crystals
·
2020
·Vol. 10
·期 9
·781
·
IF 2.404
Qintong Huang,Rui Li,Guangying Fu,Jiuxing Jiang
ZSM-5 zeolites are commonly used as a heterogeneous catalyst for reactions. Four ZSM-5 catalysts (with various crystallite sizes and a similar ratio of Si/Al) and their ball-milling/surface-poisoning derivates were used to convert L-lactic acid to L, L-lactide. The reaction products were analyzed by three independent analytical methods (i.e., Proton nuclear magnetic resonance (1H NMR), high-pressure liquid chromatography (HPLC), and chiral gas chromatography (GC)) for determining the L, L-lactide yield and L-lactic acid conversion. A clear size effect, i.e., smaller catalysts providing better performance, was observed. Further ball-milling/surface-poisoning experiments suggested that the size effect of the ZSM-5 catalysts originated from the diffusion-controlled nature of the reaction under the investigated conditions.Keywords:ZSM-5 zeolites;L,L-lactide;size effect;diffusion control
研究领域:
催化化学
·
材料科学
✓ 已验证
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2018
·
IF 8.097
Zheng Zhang,Ying Liu,Yunsheng Chen,Lexiang Li,Ping Lan,Dannong He,Jie Song,Yixin Zhang
5-Aminolevulinic acid (ALA)-loaded nanoethosome (ALA-ES) gels are successfully prepared to realize a transdermal delivery of ALA, and they provide a feasible approach for the photodynamic therapy (PDT) of hypertrophic scars (HS). Herein, the morphological and physicochemical features indicate that ALA-ES is stable in gel matrix. In vitro transdermal penetration studies suggest ALA-ES gels can overcome the compact dermal barrier and deliver more ALA into human HS tissue. In vivo delivery studies further reveal that ALA-ES gels can penetrate into rabbit HS tissue to facilitate ALA accumulating in hypertrophic scar fibroblast (HSF) and converting into protoporphyrin IX in the cytoplasm. Utilizing transmission electron microscopy, the visual in vivo penetration process indicates ALA-ES penetrate into HS tissue utilizing its deformable membrane, enters HSF by a pinocytotic-like mechanism, and then releases ALA in the cytoplasm. Subsequently, PDT efficacy is assessed using rabbit HS models. The morphological and histological analysis reveal that ALA-ES gels can improve HS by promoting HSF apoptosis, remodelling collagen fibers and increasing MMP3 expression. The results demonstrate that ALA-ES gels are suitable in clinical treatment of HS and make a substantial progress within the field.
研究领域:
药剂学
·
医学
·
生物医学工程
✓ 已验证
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）