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Core-shell-structured Composite ZSM-5@MCM-41 Catalysts:Fabrication,Characterization,and Enhanced Performance in Hexane Catalytic Cracking

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China Petroleum Processing & Petrochemical Technology 2023年第4期25卷 41-51页

作者： zhu Jiale zhu xuedong Yang Fan State Key Laboratory of Chemical Engineering School of Chemical EngineeringEast China University of Science&TechnologyShanghai 200237China

A series of core-shell zeolites with a ZSM-5 zeolite core and a MCM-41 shell with varying shell thicknesses were successfully fabricated via a cetyltrimethylammonium bromide(CTAB)-directed sol-gel coating method in an ultradilute solution. Extensive characterization techniques, including XRD, TEM, N_(2) adsorption-desorption, NH_(3)-TPD, and IR measurements, confirmed the successful coating of a microporous ZSM-5 core with a mesoporous MCM-41 shell layer and were further employed to explore the textural properties and acidic properties of the samples. The hexane cracking results revealed a significant enhancement in olefin yields after introducing the MCM-41 shell to ZSM-5. Interestingly, a volcanic trend in olefin yields was observed with the increase in the shell thickness. In particular, the highest olefin yield of 51.5%, exceeding that of the core catalyst by 17.1%, was achieved when the shell thickness was controlled at 40 nm.Moreover, the catalyst lifetime investigation revealed that the core-shell composite catalyst exhibited a minimal reduction in hexane conversion of merely 3.8% over a 120 h reaction period, significantly outperforming the 11.3% reduction exhibited by the core catalyst. This remarkable catalytic performance was attributed to the passivation of external acid sites and the introduction of more developed pore channels by the shell, which effectively mitigated unwanted side reactions. The successful synthesis of these core-shell structured catalysts presents a novel strategy for improving catalytic performance in hexane cracking, in addition to serving as a solid foundation for the design of industrial catalysts for light naphtha cracking.

关键词： catalytic cracking light olefin core-shell ZSM-5 zeolite

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Zn_(x)Zr/HZSM-5 as efficient catalysts for alkylation of benzene with carbon dioxide

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Frontiers of Chemical Science and Engineering 2023年第4期17卷 404-414页

作者： Junjun Cheng Yitao Zhao Guohao Xu Peng Zhang xuedong Zhu Fan Yang Engineering Research Center of Large-Scale Reactor Engineering and Technology Ministry of EducationEast China University of Science&TechnologyShanghai 200237China

Alkylation of benzene with carbon dioxide and hydrogen to produce toluene and xylene could increase the added-value of surplus benzene as well as relieve environmental problems like green-house effect.In this work,the alkylation benzene with carbon dioxide and hydrogen reaction was proceeded by using the mixture of zinc-zirconium oxide and HZSM-5 as bifunctional catalyst.The equivalent of Zn/Zr=1 displays the best catalytic performance at 425℃ and 3.0 MPa,and benzene conversion reaches 42.9%with a selectivity of 90%towards toluene and xylene.Moreover,the carbon dioxide conversion achieves 23.3%and the carbon monoxide selectivity is lower than 35%,indicating that more than 50%carbon dioxide has been effectively incorporated into the target product,which is the best result as far as we know.Combined with characterizations,it indicated that the Zn and Zr formed a solid solution under specific conditions(Zn/Zr=1).The as-formed solid solution not only possesses a high surface area but also provides a large amount of oxygen vacancies.Additionally,the bifunctional catalyst has excellent stabilities that could keep operating without deactivation for at least 80 h.This work provides promising industrial applications for the upgrading of aromatics.

关键词： carbon dioxide alkylation of benzene solid solution catalyst bifunctional catalyst

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Co-conversion of methanol and n-hexane into aromatics using intergrown ZSM-5/ZSM-11 as a catalyst

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Frontiers of Chemical Science and Engineering 2020年第5期14卷 783-792页

作者： Shumei Wei Yarong Xu Zhaoyang Jin xuedong Zhu UNILAB State Key Laboratory of Chemical EngineeringEast China University of Science and TechnologyShanghai 200237China Research Institute of Urumqi Petrochemical Company Petrochina Company LimitedUrumqi 830019China

The conversion of n-hexane and methanol into value-added aromatic compounds is a promising method for their industrially relevant utilization.In this study,intergrown ZSM-5/ZSM-11 crystals were synthesized and their resulting catalytic performance was investigated and compared to those of the isolated ZSM-5 and ZSM-1I zeolites.The physicochemical properties of ZSM-5/ZSM-l1 intergrown zeolite were analyzed using X-ray diffrac-tion,N2 isothermal adsorption-desorption,the tempera-ture-programmed desorption of ammonium,scanning clectron microscopy,Fourier transform infrared spectra of adsorbed pyridine,and nuclear magnetic resonance of 27AI,and compared with those of the ZSM-5 and ZSM-11 zeolites.The catalytic performances of the materials were evaluated during the co-feeding reaction of methanol and n-hexane under the fixed bed conditions of 400℃,0.5 MPa(N2),methanol:n-hexane=7:3(mass ratio),and weight hourly space velocity=1 h 1(methanol).Com-pared to the ZSM-5 and ZSM-11 zeolites,the ZSM-5/ZSM-11 zeolite exhibited the largest specific surface area,a unique crystal structure,moderate acidity,and suitable Brensted/Lewis acid ratio.The evaluation results showed that ZSM-5/ZSM-11 catalyst exhibited better catalytic reactivity than the ZSM-5 and ZSM-11 catalysts in terms of methanol conversion rate,n-hexane conversion rate,and aromatic selectivity.The outstanding catalytic property of the intergrown ZSM-5/ZSM-11 was attributed to the enhanced diffusion associated with its unique crystal.structure.The benefit of using zeolite intergrowth in the co-conversion of methanol and alkanes offers a novel route for future catalyst development.

关键词： ZSM-5/ZSM-11 methanol w-hexane cofeeding aromatics

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Dealumination and desilication for Al-rich HZSM-5 zeolite via steam-alkaline treatment and its application in methanol aromatization

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Frontiers of Chemical Science and Engineering 2019年第3期13卷 543-553页

作者： Yuehua Fang Fan Yang Xuan He xuedong Zhu State Key Laboratory of Chemical Engineering School of Chemical EngineeringEast China University of Science and TechnologyShanghai 200237China

The hierarchical HZSM-5 was prepared via dealumination and desilication of commercial Al-rich HZSM-5, and characterized by X-ray diffraction, 27Al magic-angle spinning nuclear magnetic resonance, inductively coupled plasma mass spectrometry, scanning electron microscope, transmission electron microscope, N2 adsorption-desorption, NH3 temperature-programmed desorption, performed thermogravimetric and Raman spectrum. The results showed that partial framework of HZSM-5 was removed after steam treatment at 0.15 MPa, 500℃ for 3 h. HZSM-5 with high specific surface area and much mesoporosity was obtained by the subsequent alkaline treatment. The regulation of acid quantity was achieved by altering the concentration of alkaline. Dealumination and desilication of Al-rich HZSM-5 zeolites became more effective using a combination of steam and alkaline treatments than using alkaline treatment alone. Methanol aromatization reaction was employed to evaluate the catalytic performance of treated HZSM-5 at 0.15 MPa, 450℃ and MHSV of 1.5 h^-1. The results indicated that after steam treatment, HZSM-5 further treated with 0.2 mol/L NaOH exhibits the best catalytic performance: the selectivity of aromatics reached 42.1% and the lifetime of catalyst attained 212 h, which are much better than untreated HZSM-5.

关键词： steam treatment alkaline treatment,hierarchical ZSM-5 methanol aromatization

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Alkylation of benzene with carbon dioxide to low-carbon aromatic hydrocarbons over bifunctional Zn-Ti/HZSM-5 catalyst

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Frontiers of Chemical Science and Engineering 2022年第3期16卷 384-396页

作者： Xiangyu Liu Yanling Pan Peng Zhang Yilin Wang Guohao Xu Zhaojie Su xuedong Zhu Fan Yang Engineering Research Center of Large-Scale Reactor Engineering and Technology Ministry of EducationEast China University of Science and TechnologyShanghai200237China Department of Product Engineering School of Chemical EngineeringEast China University of Science and TechnologyShanghai200237China

Alkylation of benzene to value-added,high octane number and low toxic toluene and xylenes provides a way to lower benzene content in gasoline pool,and is hence a method to promote fuel quality.On the other hand,CO_(2) accumulation in the atmosphere causes global warming and requires effective route for its valorization.Utilization of CO_(2) as a carbon source for benzene alkylation could achieve both goals.Herein,alkylation of benzene with CO_(2) and H2 was realized by a series of low-cost bifunctional catalysts containing zinc/titanium oxides(Zn/Ti oxides)and HZSM-5 molecular sieves in a fixed-bed reactor.By regulating and controlling oxygen vacancies of Zn/Ti oxides and the acidities of HZSM-5,benzene conversion and CO_(2) conversion reached 28.7%and 29.9%respectively,along with a total selectivity of toluene and xylene higher than 90%.In this process,more than 25%CO_(2) was effectively utilized and incorporated into the target products.Moreover,the mechanism of the reaction was analyzed and the course was simultaneously traced.CO_(2) was transformed into methanol firstly,and then methanol reacted with benzene generating toluene and xylene.The innovation provides a new method for upgrading of fuels and upcycling the emissions of CO_(2),which is of great environmental and economic benefits.

关键词： carbon dioxide benzene alkylation bifunctional catalyst mechanism

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Alkaline modification of ZSM-5 catalysts for methanol aromatization： The effect of the alkaline concentration

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Frontiers of Chemical Science and Engineering 2015年第4期9卷 450-460页

作者： Zhenhao Wei Tengfei Xia Minghui Liu Qingsheng Cao Yarong Xu Kake zhu xuedong Zhu State Key Laboratory of Chemical Engineering School of Chemical Engineering East China University of Science and Technology Shanghai 200237 China Research Institute of Urumchi Petrochemical Company PetroChina Company Limited Urttmchi 830019 China

The effects of alkaline treatment on the physical properties of ZSM-5 catalysts and on their activities for methanol to aromatics conversion have been investigated. A mild alkaline treatment （0.2 and 0.3 mol/L NaOH） created mesopores in the parent zeolite with no obvious effect on acidity. The presence of mesopores gives the catalyst a longer lifetime and higher selectivity for aromatics. Treatment with 0.4 mol/L NaOH decreased the number of Bronsted acid sites due to dealumination and desilication, which resulted in a lower deactivation rate. In addition, more mesopores were produced than with the mild alkaline treatment. As a result, the lifetime of the sample treated with 0.4 mol/L NaOH was almost five times that of the parent ZSM-5. Treatment with a higher alkaline concentration （0.5 mol/L） greatly reduced the number of Bronsted acid sites and the number ofmicropores resulting in incomplete methanol conversion. When the alkalinetreated catalysts were washed with acid, some of the porosity was restored and a slight increase in selectivity for aromatics was obtained.

关键词： ZSM-5 alkaline treatment dealumination,desilication mesopores methanol aromatics

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Seed-solution-induced Synthesis of FER Zeolite and Its Catalytic Application in the Skeletal Isomerization of n-Butene

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China Petroleum Processing & Petrochemical Technology 2023年第4期25卷 61-73页

作者： Fan Jinlong Yang Fan zhu xuedong Xu Yarong Chen Lantian State Key Laboratory of Chemical Engineering East China University of Science and TechnologyShanghai 200237 Research Institute of Urumqi Petrochemical Company PetrochinaUrumqi 830019

A series of Ferrierite(FER)zeolites were prepared via hydrothermal synthesis in the absence of organic templates with the aid of sodium-type FER zeolite(NaFER)or NaFER suspensions(NaFERsus)acquired by NaOH solution treatment as seeds.The differences in the structures and acid sites of the obtained FER zeolite catalysts arising from the choice of seed were investigated,and the catalytic performances of the obtained FER zeolites were evaluated in the skeletal isomerization of n-butene.The results indicate that the samples synthesized using NaFERsus feature more Br?nsted acid sites(BAS)in the 10-membered-ring(10-MR)at the expense of strong acid and Lewis acid sites(LAS),compared with samples derived from NaFER.Therefore,the FER samples synthesized using NaFERsus outperformed the NaFER counterparts as the BAS in 10-MR and LAS were the main active sites,while BAS in 8-MR and LAS were responsible for side reactions,such as polymerization,cracking,and carbon deposition in n-butene isomerization.The optimized FER catalyst was continuously used for 720 h at 350℃ at 0.1 MPa under an n-butene space velocity of 2.0 h^(-1),during which the n-butene conversion remained at>40%,and the isobutylene yield was>37.5%.

关键词： FER zeolites alkali treated seed solution n-butene skeletal isomerization

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CFD simulation of internal-loop airlift reactor using EMMS drag model

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Particuology 2015年第2期13卷 124-132页

作者： Tingting Xu xuedong Jiang Ning Yang Jiahua zhu State Key Laboratory of Multi-Phase Complex Systems Institute of Process EngineeringChinese Academy of Sciences University of Chinese Academy of Sciences Department of Chemical Engineering Xi'an Jiaotong University School of Chemical Engineering Sichuan University

The simulation of internal-loop airlift reactors is challenging because complex meso-scale structures exist in different sections of the reactor, separated by the draft tube. This paper reports on the computational fluid dynamics （CFD） simulation of internal-loop airlift reactors using a new drag model derived from the dual-bubble-size （DBS） model, an extended energy-minimization multi-scale （EMMS） approach for gas-liquid flows. Compared with the traditional Schiller-Naumann （S-N） correlation, the new model improves the simulation of gas holdup in the riser and downcomer significantly. In particular, gas holdup and circulation of two-phase flow can be modeled successfully using the new model, whereas traditional drag models such as the S-N correlation show an absence of gas in the downcomer. The simulation demonstrates the advantage and potential of this new model for internal-loop airlift reactors.

关键词： Computational fluid dynamics Internal-loop Airlift Multi-scale Multiphase flow Hydrodynamics

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Effect of Acidity on Methylation of Benzene with Methanol Catalyzed by HZSM-5:A DFT Study

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China Petroleum Processing & Petrochemical Technology 2021年第2期23卷 21-27页

作者： Wei Pifeng Fu Guangbin Mu Shanliang Gao Jichao Wen Zhenhao zhu xuedong School of Chemistry&Chemical Engineering Linyi UniversityLinyi 276000 SINOPEC Qingdao Refining and Chemical Company Ltd.Qingdao 266500 School of Chemical Engineering East China University of Science and TechnologyShanghai 200237

Different acidic HZSM-5 zeolites were constructed by doping with Al,Ga,or In.The effect of acidity on the adsorption of methylbenzenes and the reaction energy barriers for the methylation of benzene with methanol catalyzed by HZSM-5 zeolite were investigated by using the density functional theory.The results show that acidity exhibits less effect in the adsorption of methylbenzenes,while linear relationships are observed between the acidity and reaction energy barriers.As the acidity increases,the reaction energy barrier decreases linearly,and the stepwise pathway becomes dominant in strong acidity environment,while weak acidity is conducive to the concerted pathway.The calculation results could contribute to understanding the relationship between the acidity and the zeolite-catalyzed alkylation reaction of methylbenzenes.

关键词： benzene methanol methylation acidity HZSM-5

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Electrospun Semiconductor-Based Nano-Heterostructures for Photocatalytic Energy Conversion and Environmental Remediation:Opportunities and Challenges

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Energy & Environmental Materials 2023年第2期6卷 212-238页

作者： Na Lu Mingyi Zhang xuedong Jing Peng Zhang Yongan zhu Zhenyi Zhang Key Laboratory of New Energy and Rare Earth Resource Utilization of State Ethnic Affairs Commission Key Laboratory of Photosensitive Materials and Devices of Liaoning ProvinceSchool of Physics and Materials EngineeringDalian Minzu UniversityDalian 116600China Key Laboratory for Photonic and Electronic Bandgap Materials Ministry of EducationSchool of Physics and Electronic EngineeringHarbin Normal UniversityHarbin 150025China School of Materials Science and Engineering Zhengzhou UniversityZhengzhou 45001China

Harvesting solar energy to drive the semiconductor photocatalysis offers a promising tactic to address ever-growing challenges of both energy shortage and environmental pollution.Design and synthesis of nano-heterostructure photocatalysts with controllable components and morphologies are the key factors for achieving highly efficient photocatalytic processes.Onedimensional(1D)semiconductor nanofibers produced by electrospinning possess a large ratio of length to diameter,high ratio of surface to volume,small grain sizes,and high porosity,which are ideally suited for photocatalytic reactions from the viewpoint of structure advantage.After the secondary treatment of these nanofibers through the solvothermal,gas reduction,in situ doping,or assembly methods,the multi-component nanofibers with hierarchical nano-heterostructures can be obtained to further enhance their light absorption and charge carrier separation during the photocatalytic processes.In recent years,the electrospun semiconductorbased nano-heterostructures have become a“hot topic”in the fields of photocatalytic energy conversion and environmental remediation.This review article summarizes the recent progress in electrospinning synthesis of various kinds of high-performance semiconductor-based nano-heterostructure photocatalysts for H2 production,CO_(2) reduction,and decomposition of pollutants.The future perspectives of these materials are also discussed.

关键词： electrospun nanofibers energy conversion environmental remediation photocatalysis semiconductor heterojunction

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