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Influence of crystalline phase of Li-Al-O oxides on the activity of Wacker-type catalysts in dimethyl

Yadong GE, Yuanyuan DONG, Shengping WANG, Yujun ZHAO, Jing LV, Xinbin MA

《化学科学与工程前沿（英文）》 2012年 第6卷 第4期   页码 415-422 doi: 10.1007/s11705-012-1214-4

摘要： The catalysts supported on LiAl O (spinel) for vapor phase synthesis of dimethyl carbonate (DMC) from methyl nitrite (MN) have been studied. Their catalytic activities on supports prepared by different methods were evaluated in a continuous reactor. The samples were characterized by powder X-ray diffraction, N adsorption-desorption isotherms, fourier transform infrared spectroscopy and temperature-programmed reduction of H . Li/Al molar ratio and calcination temperature greatly influence the structure of crystalline phase of Li-Al-O oxides. Desirable LiAl O (spinel) was formed at 800°C, while LiAl O (primitive cube) formed at 900°C is undesirable for the reaction. A high Li/Al molar ratio, which was related with LiAlO , also slowed the reaction rate. The electron transfer ability and the interaction with active component are the important properties of the spinel-based supports. The CuCl -PdCl /LiAl O (spinel) with better electron transfer ability and low Pd reduction temperature exhibited a better catalytic ability.

关键词： Wacker-type catalyst     dimethyl carbonate     methyl nitrite     spinel    

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Rosin side chain type catalyst-free vitrimers with high cross-link density, mechanical strength, and

《化学科学与工程前沿（英文）》 2023年 第17卷 第9期   页码 1267-1279 doi: 10.1007/s11705-022-2291-7

摘要： The emergence of vitrimer, a new class of polymer materials can address the problem of recyclability, reprocess ability and recyclability of thermosetting plastics. Rosin, a natural product, is an ideal raw material for the preparation of polymers in a more sustainable way. Nevertheless, due to the huge steric hindrance caused by the hydrogenated phenanthrene ring structure, the cross-link density of materials is frequently lowered. In this study, hydrogenated rosin was adopted for preparing hydrogenated rosin side-chain type diacids, which were reacted with mixed epoxy to obtain rosin side-chain type vitrimers. It was completely characterized by differential scanning calorimetry test, thermogravimetric analysis, shape memory test and self-healing test. The prepared vitrimers exhibited good self-healing properties, excellent heat resistance (Td = 352 °C) as well as high mechanical properties (tensile strength of 46.75 MPa). The tricyclic diterpene structure of rosin was introduced into the side chain in order to avoid the reduction of cross-link density resulting from the huge steric hindrance of the rigid tricyclic hydrophenylene skeleton. Vitrimers can undergo dynamic transesterification reaction without external catalysts due to the autocatalytic effect of tertiary amines from epoxy. Moreover, our work expanded the application field of rosin, increased the added value of rosin, and provided a novel method for preparing rosin-based vitrimers with ideal properties.

关键词： vitrimers     rosin     catalyst-free     high mechanical properties     dynamic transesterification reaction    

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A new method for the synthesis of molybdovanadophosphoric heteropoly acids and their catalytic activities

ZHANG Fumin, GUO Maiping, GE Hanqing, WANG Jun

《化学科学与工程前沿（英文）》 2007年 第1卷 第3期   页码 296-299 doi: 10.1007/s11705-007-0054-0

摘要： An environmentally benign method for the synthesis of heteropoly acids HPMoVO·HO (PMoV, = 1−3) was developed by the reaction of an aqueous slurry which contained stoichiometric amounts of MoO, VO and HPO. Characterization of the as-synthesized catalysts with inductively coupled plasma (ICP) elemental analysis, thermogravimetry (TG), X-ray diffraction (XRD) and infrared (IR) spectroscopy indicated that V ions substituted for Mo ions in Keggin-type phosphomolybdic acid. The as-synthesized samples were found to be an efficient catalyst for the hydroxylation of benzene which was carried out in a mixed solvent of acetonitrile and acetic acid with aqueous hydrogen peroxide as oxidant. PMoV exhibi ted the highest benzene conversion of 34.5% with phenol selectivity of 100%.

关键词： conversion     heteropoly     Characterization     efficient catalyst     Keggin-type phosphomolybdic    

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Modeling nanostructured catalyst layer in PEMFC and catalyst utilization

Jiejing ZHANG, Pengzhen CAO, Li XU, Yuxin WANG

《化学科学与工程前沿（英文）》 2011年 第5卷 第3期   页码 297-302 doi: 10.1007/s11705-011-1201-1

摘要： A lattice model of the nanoscaled catalyst layer structure in proton exchange membrane fuel cells (PEMFC) was established by Monte Carlo method. The model takes into account all the four components in a typical PEMFC catalyst layer: platinum (Pt), carbon, ionomer and pore. The elemental voxels in the lattice were set fine enough so that each average sized Pt particulate in Pt/C catalyst can be represented. Catalyst utilization in the modeled catalyst layer was calculated by counting up the number of facets of Pt voxels where “three phase contact” are met. The effects of some factors, including porosity, ionomer content, Pt/C particle size and Pt weight percentage in the Pt/C catalyst, on catalyst utilization were investigated and discussed.

关键词： catalyst layer     PEM fuel cell     lattice model     Monte Carlo method     catalyst utilization    

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New practice in semaglutide on type-2 diabetes and obesity: clinical evidence and expectation

《医学前沿（英文）》 2022年 第16卷 第1期   页码 17-24 doi: 10.1007/s11684-021-0873-2

摘要： Obesity is an important risk factor of type 2 diabetes (T2D), which has become an important factor threatening human health. However, no perfect drug choice for obesity exists. Semaglutide is a kind of human glucagon-like peptide-1 (GLP-1) analog that promotes insulin secretion while inhibiting glucagon secretion through a glucose concentration-dependent mechanism. GLP-1 can also delay stomach emptying and suppress appetite to help lose weight. This review summarizes clinical evidence of the semaglutide effect on T2D and obesity and establishes expectations on future clinical trials for obesity treatment.

关键词： semaglutide     type 2 diabetes     obesity    

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Oxidant or catalyst for oxidation?

Jianzhi Huang, Huichun Zhang

《环境科学与工程前沿（英文）》 2019年 第13卷 第5期 doi: 10.1007/s11783-019-1158-8

摘要： Manganese oxides (MnOx) have been demonstrated to be effective materials to activate Oxone (i.e., PMS) to degrade various contaminants. However, the contribution of direct oxidation by MnOx to the total contaminant degradation under acidic conditions was often neglected in the published work, which has resulted in different and even conflicting interpretations of the reaction mechanisms. Here, the role of MnOx (as both oxidants and catalysts) in the activation of Oxone was briefly discussed. The findings offered new insights into the reaction mechanisms in PMS-MnOx and provided a more accurate approach to examine contaminant degradation for water/wastewater treatment.

关键词： Peroxymonosulfate     Manganese oxides     Catalyst     Oxidant    

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Monte Carlo simulation of the PEMFC catalyst layer

WANG Hongxing, CAO Pengzhen, WANG Yuxin

《化学科学与工程前沿（英文）》 2007年 第1卷 第2期   页码 146-150 doi: 10.1007/s11705-007-0027-3

摘要： The performance of the polymer electrolyte membrane fuel cell (PEMFC) is greatly controlled by the structure of the catalyst layer. Low catalyst utilization is still a significant obstacle to the commercialization of the PEMFC. In order to get a fundamental understanding of the electrode structure and to find the limiting factor in the low catalyst utilization, it is necessary to develop the mechanical model on the effect of catalyst layer structure on the catalyst utilization and the performance of the PEMFC. In this work, the structure of the catalyst layer is studied based on the lattice model with the Monte Carlo simulation. The model can predict the effects of some catalyst layer components, such as Pt/C catalyst, electrolyte and gas pores, on the utilization of the catalyst and the cell performance. The simulation result shows that the aggregation of conduction grains can greatly affect the degree of catalyst utilization. The better the dispersion of the conduction grains, the larger the total effective area of the catalyst is. To achieve higher utilization, catalyst layer components must be distributed by means of engineered design, which can prevent aggregation.

关键词： catalyst utilization     PEMFC     commercialization     Pt/C catalyst     conduction    

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Dendritic BiVO4 decorated with MnOx co-catalyst as an efficient hierarchical catalyst for photocatalytic

Jin Yang, Xuelian Liu, Hongbin Cao, Yanchun Shi, Yongbing Xie, Jiadong Xiao

《化学科学与工程前沿（英文）》 2019年 第13卷 第1期   页码 185-191 doi: 10.1007/s11705-018-1713-z

摘要： An appropriate co-catalyst can significantly promote the photocatalytic efficacy, but this has been seldom studied in the visible-light photocatalysis combined with ozone, namely photocatalytic ozonation. In this work, a dendritic bismuth vanadium tetraoxide (BiVO ) material composited with highly dispersed MnO nanoparticles was synthesized, and its catalytic activity is 86.6% higher than bare BiVO in a visible light and ozone combined process. Catalytic ozonation experiments, ultra-violet-visible (UV-Vis) diffuse reflectance spectra and photoluminescence spectra jointly indicate that MnO plays a triple role in this process. MnO strengthens the light adsorption and promotes the charge separation on the composite material, and it also shows good activity in catalytic ozonation. The key reactive species in this process is ·OH, and various pathways for its generation in this process is proposed. This work provides a new direction of catalyst preparation and pushes forward the application of photocatalytic ozonation in water treatment.

关键词： manganese oxide     bismuth vanadium tetraoxide     photocatalytic ozonation     hydroxyl radical     co-catalyst    

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Insight into the promotion mechanism of activated carbon on the monolithic honeycomb red mud catalyst

《环境科学与工程前沿（英文）》 2021年 第15卷 第5期 doi: 10.1007/s11783-020-1337-7

摘要：

• Activated carbon was proposed to be an efficient accelerant for molded red mud catalyst.

关键词： NOx     Selective catalytic reduction     Iron-based catalyst     Red mud     Monolithic catalyst     Activated carbon    

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Direct synthesis of diphenyl carbonate over heterogeneous catalyst: effects of structure of substitutedperovskite carrier on the catalyst activities

WU Guangwen, JIN Fang, WU Yuxin, ZHANG Guangxu, LI Dinghuo, WANG Cunwen, MA Peisheng

《化学科学与工程前沿（英文）》 2007年 第1卷 第1期   页码 59-64 doi: 10.1007/s11705-007-0012-x

摘要： The perovskite-type compound LaMnO was substituted for the part of La in position A and for the part of Mn in position B by citrate method. The phases were detected by X-ray diffraction. Powder morphologies were scanned by scanning electron microscopy. The valence of atoms was determined by X-ray photoelectron spectroscopy. It was found that the perovskite can form crystal defect and increase the proportion of high valence B element by doping. Active component Pd was loaded on various perovskite supports for synthesis of diphenyl carbonate. The results showed that the activities of catalysts in which supports have crystal defect by substitution were higher. It can be concluded that perovskite with defect structure by doping could lead to the formation of oxygen vacancy where the lattice oxygen became exchangeable with the oxygen gas. Also, this improved the redox process of the carrier by transferring electrons and activities of catalysts.

关键词： photoelectron spectroscopy     diphenyl carbonate     proportion     diffraction     perovskite    

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Personalized medicine of type 2 diabetes

null

《医学前沿（英文）》 2013年 第7卷 第1期   页码 1-3 doi: 10.1007/s11684-013-0241-y

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Pd nano-catalyst supported on biowaste-derived porous nanofibrous carbon microspheres for efficient catalysis

《化学科学与工程前沿（英文）》 2023年 第17卷 第9期   页码 1289-1300 doi: 10.1007/s11705-023-2299-7

摘要： Environmental pollution caused by the presence of aromatic aldehydes and dyes in wastewater is a serious global concern. An effective strategy for the removal of these pollutants is their catalytic conversion, possibly to valuable compounds. Therefore, the design of efficient, stable and long-lifetime catalysts is a worthwhile research goal. Herein, we used nanofibrous carbon microspheres (NCM) derived from the carbohydrate chitin present in seafood waste, and characterized by interconnected nanofibrous networks and N/O-containing groups, as carriers for the manufacture of a highly dispersed, efficient and stable Pd nano-catalyst (mean diameter ca. 2.52 nm). Importantly, the carbonised chitin’s graphitized structure, defect presence and large surface area could promote the transport of electrons between NCM and Pd, thereby endowing NCM supported Pd catalyst with high catalytic activity. The NCM supported Pd catalyst was employed in the degradation of some representative dyes and the chemoselective hydrogenation of aromatic aldehydes; this species exhibited excellent catalytic activity and stability, as well as applicability to a broad range of aromatic aldehydes, suggesting its potential use in green industrial catalysis.

关键词： biowaste chitin     nanofibrous     palladium     nano-catalyst     catalysis    

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Advanced materials: adsorbent and catalyst for environmental application

Junhua LI, Shubo DENG

《环境科学与工程前沿（英文）》 2013年 第7卷 第3期   页码 301-301 doi: 10.1007/s11783-013-0529-9

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Ni-Co bimetallic catalyst for CH

Xiaohong LI, Jun AI, Wenying LI, Dongxiong LI

《化学科学与工程前沿（英文）》 2010年 第4卷 第4期   页码 476-480 doi: 10.1007/s11705-010-0512-y

摘要： A co-precipitation method was employed to prepare Ni/Al O -ZrO , Co/Al O -ZrO and Ni-Co/Al O -ZrO catalysts. Their properties were characterized by N adsorption (BET), thermogravimetric analysis TGA , temperature-programmed reduction (TPR), temperature-programmed desorption (CO -TPD), and temperature-programmed surface reaction (CH -TPSR and CO -TPSR). Ni-Co/Al O -ZrO bimetallic catalyst has good performance in the reduction of active components Ni, Co and CO adsorption. Compared with mono-metallic catalyst, bimetallic catalyst could provide more active sites and CO adsorption sites (C+ CO = 2CO) for the methane-reforming reaction, and a more appropriate force formed between active components and composite support (SMSI) for the catalytic reaction. According to the CH -CO -TPSR, there were 80.9% and 81.5% higher CH and CO conversion over Ni-Co/Al O -ZrO catalyst, and its better resistance to carbon deposition, less than 0.5% of coke after 4 h reaction, was found by TGA. The high activity and excellent anti-coking of the Ni-Co/Al O -ZrO catalyst were closely related to the synergy between Ni and Co active metal, the strong metal-support interaction and the use of composite support.

关键词： Ni-Co bimetallic catalyst     composite support     CH4 reforming with CO2    

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Sulfonic acid-functionalized mesoporous silica catalyst with different morphology for biodiesel production

《化学科学与工程前沿（英文）》 2022年 第16卷 第8期   页码 1198-1210 doi: 10.1007/s11705-021-2133-z

摘要： Sulfonic acid functionalized mesoporous silica based solid acid catalysts with different morphology were designed and fabricated. The synthesized materials were characterized by various physicochemical and spectroscopic techniques like scanning electron microscope-energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, Brunauer–Emmett–Teller surface area, thermogravimetric analysis and n-butylamine acidity. The shape of catalysts particles plays an important role in its activity. The sulfonic acid functionalized mesoporous silica catalysts of spherical shape and the cube shape were assessed for catalytic activity in biodiesel production. The catalytic biodiesel production reaction over the catalysts were studied by esterification of free fatty acid, oleic acid with methanol. The effect of various reaction parameters such as catalyst concentration, acid/alcohol molar ratio, catalyst amount, reaction temperature and reaction time on catalytic activity were investigated to optimize the conditions for maximum conversion. It was sulfonated cubic shape mesoporous silica which exhibited better activity as compared to the spherical shape silica catalysts. Additionally, the catalyst was regenerated and reused up to three cycles without any significant loss in activity. The present catalysts exhibit superior performance in biodiesel production and it can be used for the several biodiesel feedstock’s that are rich in free fatty acids.

关键词： solid acid catalyst     mesoporous silica     sulfonic acid     biodiesel     esterification     oleic acid    

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标题 作者 时间 类型 操作

Influence of crystalline phase of Li-Al-O oxides on the activity of Wacker-type catalysts in dimethyl

Yadong GE, Yuanyuan DONG, Shengping WANG, Yujun ZHAO, Jing LV, Xinbin MA

期刊论文

Rosin side chain type catalyst-free vitrimers with high cross-link density, mechanical strength, and

期刊论文

A new method for the synthesis of molybdovanadophosphoric heteropoly acids and their catalytic activities

ZHANG Fumin, GUO Maiping, GE Hanqing, WANG Jun

期刊论文

Modeling nanostructured catalyst layer in PEMFC and catalyst utilization

Jiejing ZHANG, Pengzhen CAO, Li XU, Yuxin WANG

期刊论文

New practice in semaglutide on type-2 diabetes and obesity: clinical evidence and expectation

期刊论文

Oxidant or catalyst for oxidation?

Jianzhi Huang, Huichun Zhang

期刊论文

Monte Carlo simulation of the PEMFC catalyst layer

WANG Hongxing, CAO Pengzhen, WANG Yuxin

期刊论文

Dendritic BiVO4 decorated with MnOx co-catalyst as an efficient hierarchical catalyst for photocatalytic

Jin Yang, Xuelian Liu, Hongbin Cao, Yanchun Shi, Yongbing Xie, Jiadong Xiao

期刊论文

Insight into the promotion mechanism of activated carbon on the monolithic honeycomb red mud catalyst

期刊论文

Direct synthesis of diphenyl carbonate over heterogeneous catalyst: effects of structure of substitutedperovskite carrier on the catalyst activities

WU Guangwen, JIN Fang, WU Yuxin, ZHANG Guangxu, LI Dinghuo, WANG Cunwen, MA Peisheng

期刊论文

Personalized medicine of type 2 diabetes

null

期刊论文

Pd nano-catalyst supported on biowaste-derived porous nanofibrous carbon microspheres for efficient catalysis

期刊论文

Advanced materials: adsorbent and catalyst for environmental application

Junhua LI, Shubo DENG

期刊论文

Ni-Co bimetallic catalyst for CH

Xiaohong LI, Jun AI, Wenying LI, Dongxiong LI

期刊论文

Sulfonic acid-functionalized mesoporous silica catalyst with different morphology for biodiesel production

期刊论文