ACS Sustainable Chemistry & Engineering
·
2016
·
IF 5.267
Qiangqiang Zhu,Bin Wang,Tianwei Tan
For the effect of structural features on the catalytic performance of the conversion of ethanol and acetaldehyde to butadiene to be investigated, a series of MgO–SiO2 catalysts with different structural properties were synthesized by tuning the calcination temperature, investigated, and characterized. The best butadiene selectivity of 80.7% appears for the MgO–SiO2 catalyst calcined at 500 °C using a mixture of acetaldehyde/ethanol/water (22.5:67.5:10 wt %) as feed. Addition of the appropriate amount of water (10 wt %) improved butadiene selectivity by inhibiting the formation of 1-butanol and C6 compounds. Results from XRD, FT-IR, and 29Si MAS NMR indicate the generation of a significant amount of amorphous magnesium silicates along with few crystalline magnesium silicates for the catalyst calcined at 500 °C. XPS results indicate that it contains the lowest binding energies of both Si–O and Mg–O from Si–O–Mg bonds. For the catalysts calcined at low temperature (350 and 400 °C), more 1-butanol and C6 compounds formed, which are considered to be related to residual Mg(NO3)2. Additionally, more ethylene, diethyl ether, and butylene isomers were produced over the MgO–SiO2 catalyst calcined at 700 °C with the formation of forsterite Mg2SiO4. Further results from Fourier transform infrared spectroscopy after pyridine adsorption and CO2 temperature-programmed desorption show that the high catalytic performance is related to the presence of Lewis acidic sites and an intermediate number of basic sites.
研究领域:
催化化学
·
材料科学
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产品关联
DOI
高影响因子
ChemNanoMat
·
2021
·Vol. 7
·期 12
·1348-1354
·
IF 3.154
Jidong Bu,Chenxue Yao,Fengting Li,Shifeng Hou
Graphical A seeded growth synthetic strategy has been developed to synthesize ZIF-8 nanostructures in the form of multipods. Systematic studies were carried out to reveal the effect of several reaction parameters on the growth pattern and thus product morphology. We report a facile method to fabricate ZIF-8 nanostructures in the form of multipods. The success of this work relies on the use of seeded growth as the synthetic strategy, where uniform polyhedral ZIF-8 nanocrystals were prepared initially and served as seeds, followed by the addition of Zn precursor and imidazole to allow preferable growth to specific facets of the seeds and thus the formation of multipod structure. In particular, we were able to rationally synthesize ZIF-8 nanostructures in the form of hexapod and dendrite, respectively, using the similar seeded growth procedure, when the seed morphology was cube and truncated rhombic dodecahedron, respectively. Systematic studies were carried out to reveal the effect of several reaction parameters (e. g., seed amount and CTAB concentration) on growth pattern and thus product morphology. The current work demonstrates the feasibility and versatility of seeded growth for synthesis of colloidal metal-organic frameworks (CMOFs) with multipod structure and could find important use in fabrication of CMOFs with controlled sizes and shapes.
研究领域:
材料科学
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化学合成
✓ 已验证
产品关联
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2019
·
IF 3.131
Ya Di,Kunling Lu,Yaling Tian,Yan Liu,Yunwang Zhao,Yue Zheng
Two-phase synthesis is an advantageous alternative to the traditional synthetic method, due to its less toxicity, controllable, mild synthetic conditions and easy large-scale synthesis. However, meeting novel synthesis, the conventional trial-and-error approach could not provide a clear understanding. We herein report synthesis and mechanism investigation of CdS quantum dots in octadecene/glycerol two-phase system. The effects of different reaction parameters and conditions including reaction temperature, reaction time, reactant concentrations, and synthesis routes (one-step and two-step approach) on both nucleation and particle growth were investigated. It was found that the synthesis course was a growth dominated process depending on both CdS(monomer) and CdS(nuclei), and controlled by the interface of ODE/glycerol. The present work provided a new and clear understanding about two-phase system synthesis on semiconductor quantum dots, noble metal nanocrystals and some alloy nanomaterials .
研究领域:
材料科学
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纳米技术
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产品关联
DOI
高影响因子
Science China-Technological Sciences
·
2024
·Vol. 67
·期 8
·2413-2426
·
IF 4.4
Cheng LeiLei,Chen RuiZhe,Zhu WeiQiang,Tian ShaoNan,Gu Jing,Yuan HaoRan,Chen Yong
The hydrogenolysis/hydrocracking of waste polyethylene (PE) has recently been intensively studied, with the general pursuit of low-temperature reaction conditions, increased oil-phase yield, and narrower carbon chain distribution. Before this, we utilized a ball-milled ZSM-22 catalyst loaded with Ru nanoparticles (NPs), which exhibited excellent hydroconversion performance. It deconstructed PE into >80 wt.% oil products under low temperatures and short reaction times. Herein, we investigated the influence of varying temperature/pressure parameters on the degree of specific hydrocracking/internal hydrogenolysis/terminal hydrogenolysis reactions. From the comprehensive energy efficiency perspective, including stirring, reaction, and product separation, as well as taking into account the degree of product isomerization and catalyst lifespan, we analyzed the optimization of parameters. This research abandons the notion that lower temperatures are better and proposes a more comprehensive evaluation framework for low-consumption hydroconversion of PE to produce high-value products.
研究领域:
化学工程
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS RESEARCH BULLETIN
·
2014
·
IF 1.968
Li-Ping Jia,Qiang Zhang,Bing Yan
Mixed hydrothermal system H 2 O–OA (EDA)–O-A(LO-A) is developed to synthesize barium rare earth fluorides nanocrystals (OA = oleylamine, EDA = ethylenediamine, O-A = oleic acid and LO-A = linoleic acid). They are presented as BaREF 5 (RE = Ce, Pr, Nd, Eu, Gd, Tb, Dy, Y, Tm, Lu) and Ba 2 REF 7 (RE = La, Sm, Ho, Er, Yb). The influence of reaction parameters (rare earth species, hydrothermal system and temperature) is checked on the phase and shape evolution of the fluoride nanocrystals. It is found that reaction time and temperature of these nanocrystals using EDA (180 °C, 6 h) is lower than those of them using OA (220 °C, 10 h). The photoluminescence properties of these fluorides activated by some rare earth ions (Nd 3+ , Eu 3+ , Tb 3+ ) are studied, and especially up-conversion luminescence of the four fluoride nanocrystal systems (Ba 2 LaF 7 :Yb, Tm(Er), Ba 2 REF 7 :Yb, Tm(Er) (RE = Gd, Y, Lu)) is observed.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING RESEARCH & DESIGN
·
2017
·
IF 2.538
Lingling Zhang,Zhongyang Zhang,Xiangpo He,Feng Zhang,Zhibing Zhang
By using common cobalt(II) complex as catalyst and oxygen as oxidant, styrene could be oxidized to styrene oxide and benzaldehyde under mild conditions. The impacts of reaction parameters including catalyst amount, initial volume ratio of solvent and temperature on styrene conversion and selectivity of products were evaluated to find a way for the regulation of oxidation products of styrene. The relationship of product yield and some main parameters could be established, which help to provide the target product as more as possible. Kinetic and thermodynamic calculation were also studied for a better understanding of reaction process. Beside the reaction system, the choice of reactors is another important aspect for the regulation of the product. Airlift loop reactor and bubble column reactor were compared for the styrene oxidation reaction.
研究领域:
化学工程
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催化化学
·
反应动力学
✓ 已验证
产品关联
DOI
高影响因子
Catalysts
·
2023
·Vol. 13
·期 2
·248
·
IF 3.9
Gaokui Chen,Qiuwan Shen,Xin Zhang,Zhongwen Cai,Zicheng Shao,Shian Li,Guogang Yang
In this study, a series of A-site strontium-doped La1-xSrxCeO3-δ(x = 0.2, 0.4, 0.6, 0.8) perovskite catalysts were synthesized via the ethylenediaminetetraacetic acid (EDTA) sol-gel method for hydrogen production by methanol steam reforming. The fresh and the reduced catalysts are characterized by scanning X-ray (XRD), energy dispersive X-ray spectroscopy (EDS) and scanning electron microscopy (SEM) techniques. Results showed that La0.6Sr0.4CeO3-δexhibited the best performance among the La1-xSrxCeO3-δcatalysts. The operating parameters were optimized to study the catalytic performance of La0.6Sr0.4CeO3-δ, including catalytic temperature, water–methanol ratio (W/M) and liquid hourly space velocity (LHSV). However, the excessive strontium content led to a decrease in hydrogen production amount per unit time, and the high W/M promoted the reverse water–gas shift reaction (RWGS), which resulted in a decrease in CO selectivity and an increase in CO2selectivity. In addition, the optimal reaction parameters are as follows: reforming temperature of 700 °C; W/M of 3:1; LHSV of 20 h−1. Furthermore, the methanol conversion rate of La0.6Sr0.4CeO3-δcan reach approximately 82%, the hydrogen production can reach approximately 3.26 × 10−3mol/g(cat)/min under the optimum reaction conditions. Furthermore, La0.6Sr0.4CeO3-δexhibits high hydrogen selectivity (85%), which is a promising catalyst for MSR application.
研究领域:
化学工程
·
催化材料科学
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产品关联
DOI
高影响因子
Materials Research Express
·
2020
·Vol. 7
·期 7
·075501
·
IF 1.929
Dinh Trinh Tran,Van Noi Nguyen
Reduced graphite oxide (rGO) was synthesized from graphene oxide (GO) by reduction process with the aid of ascorbic acid. GO was synthesized from graphite precursor by modified Hummers method. The prepared materials were characterized in terms of surface morphology, structure, functional group, and elemental compositions by different methods such as SEM/EDS, XRD, FT-IR, Raman, and BET. rGO/K2S2O8 system was used to study the impact of different reaction parameters on the degradation of tetracycline in water. The results showed that GO and rGO materials were successfully synthesized, with high purity. The prepared rGO promoted the degradation of tetracycline by sulphate radicals generated from K2S2O8 with an efficiency of two-fold higher than sole K2S2O8. More than 95% of 5 mg l−1 tetracycline were removed by rGO/K2S2O8 system after 40 min of reaction. The catalytic performance of rGO/K2S2O system in the degradation of tetracycline was dependent on pH of the solution, catalyst loading, tetracycline initial concentration, and persulfate concentration. The optimal conditions for the degradation of tetracycline in water were at pH10, with 5 mg l−1 tetracycline initial concentration, 20 mg l−1 of rGO, and 0.2 mM persulfate added. The catalytic performance of the system showed relatively stable, with about 75% tetracycline in solution were removed after 3 cycles. The degradation of tetracycline by rGO/K2S2O8 system followed the pseudo-first order kinetics, with a typical coefficient of determination above 0.95 for all experimental conditions.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2022
·Vol. 140
·期 3
·e53320
·
IF 3.057
Lijun Guo,Yuxin Gao,Jin Huang,Jingqi Xue,Feng Li,Cuiqin Li
The functionalized covalent organic framework materials play an important role in catalytic application. A convenient tactic is developed to design and synthesize an imine-linked covalent organic frameworks (COFs) material (COF-PD) with abundant nitrogen atoms, which can provide coordination active site and facilitate the incorporation of COFs with nickel ions. Nickel-coordinated COF-PD complex (COF-PD-Ni) is prepared and used in ethylene oligomerization. COF-PD-Ni displays the highest catalytic activity of 1.98 × 10 5 g/(mol·Ni·h) in ethylene oligomerization with MAO as co-catalyst and cyclohexane as solvent. Various reaction parameters including reaction temperature, time, solvent, and the amount of cocatalyst are evaluated in detail, dramatically impacting the catalytic activities as well as the distribution of the products. What is more, the effect of COFs structure on the catalytic performance is also studied, suggesting more coordination sites were more important for high activity.
研究领域:
材料科学
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催化化学
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产品关联
DOI
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2022
·
IF 3.898
Qingjun Zhang,Youguang Ma,Xigang Yuan,Aiwu Zeng
A feasible synthesis route is developed for achieving the direct carboxylation of thiophene and CO 2 in a relatively mild solvent-free carboxylate-assisted carbonate (semi) molten state. The effects of reaction factors on the carboxylate yield are investigated in the preliminary screening experiments, and the phase behavior analysis of the reaction medium is detected through the thermal characterization analysis of in-situ high temperature X-ray diffraction measurement ( in-situ XRD). The application of response surface methodology (RSM) based on the Box-Behnken design (BBD) is conducted to investigate the effect of the reaction parameters, such as reaction temperature, carbonate proportion, CO 2 pressure and thiophene amount, on the product yield. The regressed second-order polynomial model equation well correlates all the independent variables. The analysis of variance (ANOVA) results reveal that the quadratic effect of reaction temperature is the most effective parameter in this carboxylation reaction owing to it’s the highest contribution to the sum of square (30.18%). The optimum reaction conditions for maximum product yield are the reaction temperature of 287 °C, carbonate proportion of 32.20%, CO 2 pressure of 1.0MPa and thiophene amount of 9.35 mmol. Operating under these selected experimental conditions, a high product yield (50.98%) can be achieved.
研究领域:
化学工程
·
有机化学
·
催化
✓ 已验证
产品关联
DOI
高影响因子
FOOD CHEMISTRY
·
2022
·
IF 9.231
Xue Xia,Yun Zhai,Heping Cui,Han Zhang,Khizar Hayat,Xiaoming Zhang,Chi-Tang Ho
The Amadori compound of glucose and l -alanyl- l -glutamine (Ala-Gln-ARP) was prepared and characterized by UPLC-MS/MS and NMR. There were no pyrazines produced by heated Ala-Gln-ARP alone due to the asynchronicity of regenerated l -alanyl- l -glutamine and α -dicarbonyl compounds. High temperature (130 °C) and long reaction time could facilitate the 2,5-dimethylpyrazine formation at a small concentration (33.4 ± 3.47 μg/L). The exogenous amino substrates would lower the formation temperature of pyrazines and make it to be generated effectively. Extra supplied l -alanyl- l -glutamine could generate 2,5-dimethylpyrazine at 110 °C, while higher temperature of 140 °C could strengthen the formation of 2,5-dimethylpyrazine (793 ± 119 μg/L) and stimulate the generation of other pyrazines, including methylpyrazine and 2,6-dimethylpyrazine. The exogenous alanine, glutamic acid, and glutamine was also beneficial to enhance the pyrazines formation, especially the glutamic acid. Furthermore, alkaline pH of thermal reaction made pyrazines increase significantly than in neutral medium and further enriched their species such as unsubstituted pyrazine and trimethylpyrazine.
研究领域:
食品化学
·
有机化学
·
分析化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
APPLIED ORGANOMETALLIC CHEMISTRY
·
2018
·Vol. 32
·期 4
·e4285
·
IF 3.581
Zhiquan Yang,Jie Ding,Jinna Feng,Chong He,Ying Li,Xiaowen Tong,Xiaojun Niu,Hongguo Zhang
Because of their desired features, including very specific surface areas and designable framework architecture together with their possibility to be functionalized, Metal Framework (MOF) is a promising platform for supporting varied materials in respect of catalytic applications in water treatment. In this work, a novel visible-light-responsive photocatalyst that comprised BiVO 4 together with MIL-125(Ti), was synthesized by a two-step hydrothermal approach. The characterization of as-obtained samples as performed by X-ray diffraction, scanning electron microscopy, high resolution transmission electron microscopy, Fourier transform infrared spectroscope, X-ray photoelectron spectroscopy and ultraviolet-visible diffuse reflection spectra. Rhodamine B was selected being a target for the evaluation of the photocatalytic function of as-developed photocatalyst. The photocatalytic reaction parameters, for example, the content of BiVO 4 as well as initial concentration of Rhodamine B was researched. The composite photocatalyst possessing Bi:Ti molar ratio of 3:2 brought to light the fact that the greatest photocatalytic activity had the ability to degrade 92% of Rhodamine B in 180 min. In addition to that, the BiVO 4 /MIL-125(Ti) composite could keep its photocatalytic activity during the recycling test. The phenomenon of disintegration of the photo-generated charges in the BiVO 4 /MIL-125(Ti) composite was brought to discussion as well.
研究领域:
材料科学
·
环境科学
·
催化
·
水处理
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）