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Enhanced performances in catalytic oxidation of

Nanli QIAO,Xin ZHANG,Chi HE,Yang LI,Zhongshen ZHANG,Jie CHENG,Zhengping HAO

《环境科学与工程前沿(英文)》 2016年 第10卷 第3期   页码 458-466 doi: 10.1007/s11783-015-0802-1

摘要: A series of hierarchical macro-/mesoporous silica supports (MMSs) were successfully synthesized using dual-templating technique employing polystyrene (PS) spheres and the Pluronic P123 surfactant. Pd was next loaded on the hierarchical silica supports via colloids precipitation method. Physicochemical properties of the synthesized samples were characterized by various techniques and all catalysts were tested for the total oxidation of -xylene. Among them, the Pd/MMS-b catalyst with tetraethoxysilane/polystyrene weight ratio of 1.0 exhibited superior catalytic activity, and under a higher gas hourly space velocity (GHSV) of 70000 h , the 90% conversion of -xylene has been obtained at around 200°C. The BET and SEM results indicated that Pd/MMS-b catalyst possesses high surface area and large pore volume, and well-ordered, interconnected macropores and 2D hexagonally mesopores hybrid network. This novel ordered hierarchical porous structure was highly beneficial to the dispersion of active sites Pd nanoparticles with less aggregation, and facilitates diffusion of reactants and products. Furthermore, the Pd/MMS-b catalyst possessed good stability and durability.

关键词: hierarchical macro-/mesoporous     silica     palladium     VOCs catalytic oxidation    

Template-free synthesis of hierarchically macro-mesoporous Mn-TiO

Zhao Peng, Li-Hua Chen, Ming-Hui Sun, Pan Wu, Chang Cai, Zhao Deng, Yu Li, Wei-Hong Zheng, Bao-Lian Su

《化学科学与工程前沿(英文)》 2018年 第12卷 第1期   页码 43-49 doi: 10.1007/s11705-017-1679-2

摘要: This study described a template-free method for the synthesis of hierarchically macro-mesoporous Mn-TiO catalysts. The promoting effect of Mn doping and the hierarchically macro-mesoporous architecture on TiO based catalysts was also investigated for the selective reduction of NO with NH . The results show that the catalytic performance of TiO based catalysts was improved greatly after Mn doping. Meanwhile, the Mn-TiO catalyst with the hierarchically macro-mesoporous architecture has a better catalytic activity than that without such an architecture.

关键词: titania     hierarchically macro-mesoporous structure     Mn-doping     selective catalytic reduction    

Progressive failure analysis of notched composite plate by utilizing macro mechanics approach

《结构与土木工程前沿(英文)》 2021年 第15卷 第3期   页码 623-642 doi: 10.1007/s11709-021-0726-8

摘要: In this study, gradual and sudden reduction methods were combined to simulate a progressive failure in notched composite plates using a macro mechanics approach. Using the presented method, a progressive failure is simulated based on a linear softening law prior to a catastrophic failure, and thereafter, sudden reduction methods are employed for modeling a progressive failure. This combination method significantly reduces the computational cost and is also capable of simultaneously predicting the first and last ply failures (LPFs) in composite plates. The proposed method is intended to predict the first ply failure (FPF), LPF, and dominant failure modes of carbon/epoxy and glass/epoxy notched composite plates. In addition, the effects of mechanical properties and different stacking sequences on the propagation of damage in notched composite plates were studied. The results of the presented method were compared with experimental data previously reported in the literature. By comparing the numerical and experimental data, it is revealed that the proposed method can accurately simulate the failure propagation in notched composite plates at a low computational cost.

关键词: progressive failure     notched composite plate     Hashin failure criterion     macro mechanics approach     finite element method    

Chloride ingress and macro-cell corrosion of steel in concrete made with recycled brick aggregate

《结构与土木工程前沿(英文)》 2021年 第15卷 第6期   页码 1358-1371 doi: 10.1007/s11709-021-0769-x

摘要: An investigation on chloride ingress and macro-cell corrosion of steel bars in concrete made with recycled brick aggregate (RBA) was carried out. As control cases, virgin brick aggregate (BA) and stone aggregate (SA) were also investigated. Both cylindrical and cracked prism specimens were studied for 16 different cases. The prism specimens were made with a segmented steel bar providing electrical connection from outside of the specimens to measure macro-cell corrosion current continuously under seawater splash exposure for a period of 30 d using a data logger. Cylindrical specimens were submerged in 3% NaCl solution at a temperature of 40°C to investigate chloride ingress in concrete made with RBA, BA, and SA after 120 and 180 d. Half-cell potential, corrosion area, and depths of corrosion were also investigated. The chloride ingress as well as corrosion of steel bars in concrete made with the different types of aggregate is ordered as RBA > BA > SA.

关键词: brick aggregate     chloride ingress     macro-cell corrosion     recycled brick aggregate    

Review on research and application of mesoporous transitional metal oxides in water treatment

Minghao SUI, Lei SHE

《环境科学与工程前沿(英文)》 2013年 第7卷 第6期   页码 795-802 doi: 10.1007/s11783-013-0521-4

摘要: This paper reviews the application of mesoporous transitional metal oxides in water treatment on basis of the catalysis and adsorption. Mesoporous transitional metal oxides are characterized by their intrinsic features, such as a high surface area, a highly ordered array of unidimensional pores with a very narrow pore size distribution, and highly dispersed active sites. Finally, the suggestions of further study on application are proposed.

关键词: mesoporous materials     transitional metal oxides     catalysis     adsorption     water treatment    

Enhanced activation of persulfate using mesoporous silica spheres augmented Cu–Al bimetallic oxide particles

《化学科学与工程前沿(英文)》 2023年 第17卷 第10期   页码 1581-1592 doi: 10.1007/s11705-023-2327-7

摘要: Herein, Cu–Al bimetallic oxide was synthesized and mixed with mesoporous silica spheres via a simple hydrothermal method. The prepared sample was then analyzed and employed to activate potassium peroxydisulfate for bisphenol A removal. Based on the results of X-ray diffraction, scanning electron microscopy, and energy dispersion spectroscopy, Cu–Al bimetallic oxide was determined as CuO-Al2O3, and mesoporous silica spheres were found around the these particles. At 30 min, a bisphenol A degradation level of 90% was achieved, and it remained at over 60% after five consecutive cycles, indicating the catalyst’s superior capacity and stability. In terms of removal performance, the radical pathway (including SO4•‒, OH •, and O2•‒) and singlet oxygen (1O2) played minor roles, while electron migration between bisphenol A, potassium peroxydisulfate, and the catalyst played a dominant role. The introduction of Al2O3 promoted the formation of surface oxygen vacancies, which improved ligand complex formation between potassium peroxydisulfate and the catalyst, thereby facilitating electron migration. Furthermore, mesoporous silica spheres augment not only enhanced bisphenol A adsorption but also alleviated Cu leaching. Overall, this work is expected to provide significant support for the rational development of catalysts with high catalytic activity for persulfate activation via surface electron migration.

关键词: Cu–Al bimetallic oxides     mesoporous silica spheres     peroxydisulfate     bisphenol A    

Synthesis of ordered cerium-doped cubic mesoporous silica using long-chain ionic liquid as template

YUE Hongxia, ZHAO Hongmei, LIU Longjiang, WANG Siping, Ruan Qiong, WANG Tongwen

《化学科学与工程前沿(英文)》 2008年 第2卷 第2期   页码 135-139 doi: 10.1007/s11705-008-0031-2

摘要: The long-chain ionic liquid 1-hexadecyl-3-methylimidazolium chloride (CmimCl) was used as a template to prepare cerium-doped MCM-48 materials in basic medium by a hydrothermal synthesis procedure. The effect of the amount of Ce salt and CmimCl/Si on the synthesis were discussed in detail. This mesoporous material exhibits a pore architecture which is cubic 3 gyroid and possesses a large surface area and a narrow pore distribution. Cerium in calcined porous framework exists in the form of well-dispersed tetrahedral coordination. The CmimCl shows a high tendency toward self-aggregation that allows the formation of the cerium-doped gyroid mesostructure by using the appropriate amount of Ce salt.

关键词: mesoporous     CmimCl/Si     tendency     mesostructure     synthesis procedure    

Ti incorporation in MCM-41 mesoporous molecular sieves using hydrothermal synthesis

Shengping WANG, Changqing MA, Yun SHI, Xinbin MA

《化学科学与工程前沿(英文)》 2014年 第8卷 第1期   页码 95-103 doi: 10.1007/s11705-014-1405-2

摘要: Titanium-containing mesoporous materials (Ti-MCM-41) were obtained by hydrothermal synthesis. Such materials are active catalysts for the transesterification of dimethyl oxalate and phenol to produce diphenyl oxalate. To understand the role of the Ti in the catalytic process, Ti-MCM-41 samples with different Si/Ti ratios (from 5 to 100) were prepared and the samples were analyzed by Fourier transform infrared spectroscopy, UV-visible spectroscopy, and ammonia temperature programmed desorption. It was concluded that the Ti is incorporated into the framework of the MCM-41 and formed weak Lewis acid sites. In addition, the number of Ti(IV) sites increased as the amount of titanium increased. X-ray powder diffraction, N adsorption-desorption and transmission electron microscopy results showed that the Ti-MCM-41 samples have a hexagonal arrangement of mono-dimensional pores. A large number of Ti(IV) sites coupled with the mesoporous structure and large pore diameters are favorable for the transesterification catalytic properties of Ti-MCM-41.

关键词: Ti-MCM-41     mesoporous molecular sieve     acid sites     transesterification     hydrothermal synthesis    

Deep convolutional tree-inspired network: a decision-tree-structured neural network for hierarchical

《机械工程前沿(英文)》 2021年 第16卷 第4期   页码 814-828 doi: 10.1007/s11465-021-0650-6

摘要: The fault diagnosis of bearings is crucial in ensuring the reliability of rotating machinery. Deep neural networks have provided unprecedented opportunities to condition monitoring from a new perspective due to the powerful ability in learning fault-related knowledge. However, the inexplicability and low generalization ability of fault diagnosis models still bar them from the application. To address this issue, this paper explores a decision-tree-structured neural network, that is, the deep convolutional tree-inspired network (DCTN), for the hierarchical fault diagnosis of bearings. The proposed model effectively integrates the advantages of convolutional neural network (CNN) and decision tree methods by rebuilding the output decision layer of CNN according to the hierarchical structural characteristics of the decision tree, which is by no means a simple combination of the two models. The proposed DCTN model has unique advantages in 1) the hierarchical structure that can support more accuracy and comprehensive fault diagnosis, 2) the better interpretability of the model output with hierarchical decision making, and 3) more powerful generalization capabilities for the samples across fault severities. The multiclass fault diagnosis case and cross-severity fault diagnosis case are executed on a multicondition aeronautical bearing test rig. Experimental results can fully demonstrate the feasibility and superiority of the proposed method.

关键词: bearing     cross-severity fault diagnosis     hierarchical fault diagnosis     convolutional neural network     decision tree    

The modification of titanium in mesoporous silica for Co-based Fischer–Tropsch catalysts

《化学科学与工程前沿(英文)》 2022年 第16卷 第8期   页码 1224-1236 doi: 10.1007/s11705-022-2139-1

摘要: Ordered SBA-15 mesoporous silica with incorporated titanium was successfully synthesized via a one-pot hydrothermal crystallization method. The characterization including powder X-ray diffraction, Brunauer–Emmett–Teller, transmission electron microscope, temperature-programmed reduction, temperature-programmed desorption, Fourier transform infrared and ultraviolet-visible-near infrared spectrometer was performed to explore the physical and chemical structures of both the supports and the catalysts. The results showed that titanium was successfully incorporated into the mesoporous silica framework with a limited amount of titanium (Si/Ti > 20), and the mesoporous structure was retained. However, the increased titanium content inevitably resulted in the formation of anatase TiO 2 particles on the support surface. The increased incorporated titanium strengthened the interactions between cobalt species and supports, which was favorable for the cobalt species dispersion, despite the limited cobalt oxide reducibility. The enhanced metal-support interactions were beneficial for the CO/H2 ratio at the active cobalt sites, which facilitated the formation of more C5+ hydrocarbons. This study provides a promising method for support modification with incorporated-heteroatoms for the rational development of Fischer–Tropsch catalysts.

关键词: Fischer–Tropsch synthesis     titanium incorporation     mesoporous silica     metal-support interactions     C5+ selectivity    

Copper nanoparticles/polyaniline-derived mesoporous carbon electrocatalysts for hydrazine oxidation

Tao Zhang, Tewodros Asefa

《化学科学与工程前沿(英文)》 2018年 第12卷 第3期   页码 329-338 doi: 10.1007/s11705-018-1741-8

摘要:

Copper nanoparticles-decorated polyaniline-derived mesoporous carbon that can serve as noble metal-free electrocatalyst for the hydrazine oxidation reaction (HzOR) is synthesized via a facile synthetic route. The material exhibits excellent electrocatalytic activity toward HzOR with low overpotential and high current density. The material also remains stable during the electrocatalytic reaction for long time. Its good electrocatalytic performance makes this material a promising alternative to conventional noble metal-based catalysts (e.g., Pt) that are commonly used in HzOR-based fuel cells.

关键词: copper nanoparticles     mesoporous carbon     noble metal-free electrocatalyst     hydrazine oxidation reaction     polyaniline    

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    

Atomistic simulations for adsorption and separation of flue gas in MFI zeolite and MFI/MCM-41 micro/mesoporous

Shengchi ZHUO, Yongmin HUANG, Jun HU, Honglai LIU

《化学科学与工程前沿(英文)》 2011年 第5卷 第2期   页码 264-273 doi: 10.1007/s11705-010-1007-6

摘要: Adsorption of pure CO and N and separation of CO /N mixture in MFI zeolite and MFI/MCM-41 micro/mesoporous composite have been studied by using atomistic simulations. Fully atomistic models of MFI and MFI/MCM-41 are constructed and characterized. A bimodal pore size distribution is observed in MFI/MCM-41 from simulated small- and broad-angle X-ray diffraction patterns. The density of MFI/MCM-41 is lower than MFI, while its free volume and specific surface area are greater than MFI due to the presence of mesopores. CO is preferentially adsorbed than N , and thus, the loading and isosteric heat of CO are greater than N in both MFI and MFI/MCM-41. CO isotherm in MFI/MCM-41 is similar to that in MFI at low pressures, but resembles that in MCM-41 at high pressures. N shows similar amount of loading in MFI, MCM-41 and MFI/MCM-41. The selectivity of CO over N in the three adsorbents decreases in the order of MFI>MFI/MCM-41>MCM-41. With increasing pressure, the selectivity increases in MFI and MFI/MCM-41, but decreases in MCM-41. The self-diffusivity of CO and N in MFI decreases as loading increases, while in MFI/MCM-41, it first increases and then drops.

关键词: adsorption     diffusion     CO2     flue gas     zeolite     micro/mesoporous composite    

Enhancing the photoelectrochemical performance of p-silicon through TiO coating decorated with mesoporous

《能源前沿(英文)》 2021年 第15卷 第3期   页码 772-780 doi: 10.1007/s11708-021-0783-7

摘要: MoS2 is a promising electrocatalyst for hydrogen evolution reaction and a good candidate for cocatalyst to enhance the photoelectrochemical (PEC) performance of Si-based photoelectrode in aqueous electrolytes. The main challenge lies in the optimization of the microstructure of MoS2, to improve its catalytic activity and to construct a mechanically and chemically stable cocatalyst/Si photocathode. In this paper, a highly-ordered mesoporous MoS2 was synthesized and decorated onto a TiO2 protected p-silicon substrate. An additional TiO2 necking was introduced to strengthen the bonding between the MoS2 particles and the TiO2 layer. This meso-MoS2/TiO2/p-Si hybrid photocathode exhibited significantly enhanced PEC performance, where an onset potential of +0.06 V (versus RHE) and a current density of −1.8 mA/cm2 at 0 V (versus RHE) with a Faradaic efficiency close to 100% was achieved in 0.5 mol/L H2SO4. Additionally, this meso-MoS2/TiO2/p-Si photocathode showed an excellent PEC ability and durability in alkaline media. This paper provides a promising strategy to enhance and protect the photocathode through high-performance surface cocatalysts.

关键词: photoelectrocatalysis     hydrogen evolution     Si photocathode     mesoporous MoS2    

Effect of the degree of template removal from mesoporous silicate materials on their adsorption of heavy

Farouq TWAIQ,M.S. NASSER,Sagheer A. ONAIZI

《化学科学与工程前沿(英文)》 2014年 第8卷 第4期   页码 488-497 doi: 10.1007/s11705-014-1459-1

摘要: The key aim of this study is to evaluate the adsorption of heavy oil from aqueous solutions with different oil contents over mesoporous silicate materials having different surfactant template contents. The mesoporous silicate materials have been synthesized from tetraethylorthosilicate as a silica precursor and cetyltrimethylammonium bromide as a template using the sol-gel technique. Four samples were prepared by (1) totally removing the template using the calcination process, (2) partially removing the template via ethanol extraction, (3) partially removing the template via water extraction, and (4) keeping the template as synthesized, respectively. These four samples have been characterized using X-ray diffraction, nitrogen adsorption, thermal gravimetric analysis and Fourier transformed infrared. The effect of the degree of template removal of these mesoporous materials for the oil removal has been investigated. The oil removal is inversely proportional to the surfactant content in the mesoporous material, being highest for the calcined sample but lowest for the as-synthesized sample. The kinetic of oil adsorption over the calcined material has been also studied and the data obtained fit well a second-order model.

关键词: heavy oil     mesoporous silicate material     kinetics     template removal     adsorption    

标题 作者 时间 类型 操作

Enhanced performances in catalytic oxidation of

Nanli QIAO,Xin ZHANG,Chi HE,Yang LI,Zhongshen ZHANG,Jie CHENG,Zhengping HAO

期刊论文

Template-free synthesis of hierarchically macro-mesoporous Mn-TiO

Zhao Peng, Li-Hua Chen, Ming-Hui Sun, Pan Wu, Chang Cai, Zhao Deng, Yu Li, Wei-Hong Zheng, Bao-Lian Su

期刊论文

Progressive failure analysis of notched composite plate by utilizing macro mechanics approach

期刊论文

Chloride ingress and macro-cell corrosion of steel in concrete made with recycled brick aggregate

期刊论文

Review on research and application of mesoporous transitional metal oxides in water treatment

Minghao SUI, Lei SHE

期刊论文

Enhanced activation of persulfate using mesoporous silica spheres augmented Cu–Al bimetallic oxide particles

期刊论文

Synthesis of ordered cerium-doped cubic mesoporous silica using long-chain ionic liquid as template

YUE Hongxia, ZHAO Hongmei, LIU Longjiang, WANG Siping, Ruan Qiong, WANG Tongwen

期刊论文

Ti incorporation in MCM-41 mesoporous molecular sieves using hydrothermal synthesis

Shengping WANG, Changqing MA, Yun SHI, Xinbin MA

期刊论文

Deep convolutional tree-inspired network: a decision-tree-structured neural network for hierarchical

期刊论文

The modification of titanium in mesoporous silica for Co-based Fischer–Tropsch catalysts

期刊论文

Copper nanoparticles/polyaniline-derived mesoporous carbon electrocatalysts for hydrazine oxidation

Tao Zhang, Tewodros Asefa

期刊论文

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

期刊论文

Atomistic simulations for adsorption and separation of flue gas in MFI zeolite and MFI/MCM-41 micro/mesoporous

Shengchi ZHUO, Yongmin HUANG, Jun HU, Honglai LIU

期刊论文

Enhancing the photoelectrochemical performance of p-silicon through TiO coating decorated with mesoporous

期刊论文

Effect of the degree of template removal from mesoporous silicate materials on their adsorption of heavy

Farouq TWAIQ,M.S. NASSER,Sagheer A. ONAIZI

期刊论文