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沸石整体结构的刚性与局部孔道的柔性

化学进展 2022年第5期34卷 1013-1014页

作者：肖丰收浙江大学化学与生物工程学院杭州310028

沸石分子筛(zeolite)是一类极为重要的多孔晶体材料,其结构由TO_(4)(T=Si、Al、P等)四面体通过桥氧共顶点连接构成,构成了孔径为0.3~1.3 nm的均一孔道结构[1,2],广泛地应用于石油炼制、石油化工、煤化工、日用化工等领域。当前,全球沸... 详细信息

沸石分子筛(zeolite)是一类极为重要的多孔晶体材料,其结构由TO_(4)(T=Si、Al、P等)四面体通过桥氧共顶点连接构成,构成了孔径为0.3~1.3 nm的均一孔道结构[1,2],广泛地应用于石油炼制、石油化工、煤化工、日用化工等领域。当前,全球沸石分子筛市值超过200亿美元以上,由沸石分子筛衍生的产值已高达十万亿美元量级。通过调控孔道的大小,可以高效筛分催化与吸附过程中的分子,让那些小于沸石孔径的分子通过而阻碍大于沸石孔径的分子吸附,这一现象被人们称之为沸石孔道结构的择形[3]。然而,在许多情况下,从晶体结构计算的孔道结构尺寸小于在催化转化与吸附过程中分子的筛分尺寸,长期以来人们揣测这种差异也许与沸石孔道结构的局部灵活变形有关,但是一直没有直接证据[4,5]。

关键词：沸石分子筛晶体结构孔道结构晶体材料分子吸附石油炼制催化转化石油化工

Solvent-free synthesis of zeolite catalysts

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Science China Chemistry 2015年第1期58卷 6-13页

作者： Xiangju Meng Qinming Wu Fang Chen feng-shou xiao Key Lab of Applied Chemistry of Zhejiang Province Department of Chemistry Zhejiang University

The most used method for preparation of zeolites is hydrothermal synthesis from silicate or aluminosilicate gels at temperatures in the range of 60–200°*** water used in the industrial process results in several issues,including high autogeneous pressure,low efficiency,pollution,*** solve these problems,several strategies have been *** review describes the solvent-free synthesis of *** combination of solvent-free synthesis and organotemplate-free synthesis can open the pathway to a highly sustainable zeolite synthesis protocol in industry.

关键词：无溶剂合成沸石催化剂水热合成工业过程硅铝酸盐合成沸石沸石合成硅酸盐

Fischer-Tropsch reaction within zeolite crystals for selective formation of gasoline-ranged hydrocarbons

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Journal of Energy Chemistry 2021年第3期30卷 429-433页

作者： Chengtao Wang Wei Fang Liang Wang feng-shou xiao Key Lab of Biomass Chemical Engineering of Ministry of Education College of Chemical and Biological EngineeringZhejiang UniversityHangzhou 310027ZhejiangChina Department of Chemistry Zhejiang UniversityHangzhou 310028ZhejiangChina

Product selectivity control is attractive in Fischer-Tropsch(F-T)synthesis but it is still a challenge,because the F-T products follow the Anderson-Schulz-Flory(ASF)distribution with maximized gasoline-ranged(C_(5)-C_(11))hydrocarbon selectivity at 45%.Herein,we report a strategy by optimizing the gasoline selectivity to outperform the ASF *** key to this success is fixation of the metal nanoparticles within zeolite crystals(metal@zeolite),where the zeolite micropore adjusts the product *** example,the Ru@NaY exhibited the gasoline selectivity 64.3% in the F-T reaction,which is significantly higher than the ASF limitation and about 2 times of that(32.8%)over conventionally supported Ru catalyst(Ru/NaY).This investigation might offer an alternative route for the direct transformation of syngas to liquid fuels with controllable selectivities.

关键词： F-T synthesis Zeolite Ru nanoparticles Gasoline

Insights into the Organotemplate-Free Synthesis of Zeolite Catalysts

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Engineering 2017年第4期3卷 567-574页

作者： Yeqing Wang Qinming Wu Xiangju Meng feng-shou xiao Key Lab of Applied Chemistry of Zhejiang Province Department of Chemistry Zhejiang University Hangzhou 310007 China

As the most important nanoporous material, zeolites, which have intricate micropores, are essential heterogeneous catalysts in industrial processes. Zeolites are generally synthesized with organic templates under hydrothermal conditions; however, this method is environmentally unfriendly and costly due to the formation of harmful gases and polluted water. This article briefly summarizes the role of organic templates and describes designed routes for the organotemplate-free synthesis of zeolites, aided by zeolite seeds and zeolite seeds solution. Furthermore, this review explicates that the micropore volume decreases with an increase of the Si/Al ratios in the organotemplate-free synthesis of zeolite products, where Na+ exists as an alkali cation. This feature is very important in directing the synthesis of zeolite catalysts with controllable Si/Al ratios under organotemplate-free conditions, and is thus important for the efficient design of zeolites.

关键词： Zeolite seed-directed synthesis Organotemplate-free synthesis Zeolite seeds solution Si/Al ratios Zeolite micropore volume

Mesoporous zeolites for biofuel upgrading and glycerol conversion

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Frontiers of Chemical Science and Engineering 2018年第1期12卷 132-144页

作者： Jian Zhang Liang Wang Yanyan Ji Fang Chen feng-shou xiao Key Laboratory of Applied Chemistry of Zhejiang Province and Department of Chemistry Zhejiang University Hangzhou 310028 China Key Laboratory of Biomass Chemical Engineering of Ministry of Education Zhejiang University Hangzhou 310027 China

With the recent emphasis and development of sustainable chemistry, the conversion of biomass feed- stocks into alternative fuels and fine chemicals over various heterogeneous catalysts has received much attention. In particular, owing to their uniform micropores, strong acidity, and stable and rigid frameworks, zeolites as catalysts or co-catalysts have exhibited excellent catalytic performances in many reactions, including hydrodesulfurization, Fischer-Tropsch synthesis, and hydrodeoxygenation. However, the relatively small sizes of the zeolite micropores strongly limit the conversion of bulky biomolecules. To overcome this issue, mesoporous zeolites with pores larger than those of biomolecules have been synthesized. As expected, these mesoporous zeolites have outperformed conventional zeolites with improved activ- ities, better selectivities, and longer catalyst lives for the upgrading of pyrolysis oils, the transformation of lipids into biofuels, and the conversion of glycerol into acrolein and aromatic compounds. This review briefly summarizes recent works on the rational synthesis of mesoporous zeolites and their superior catalytic properties in biomass conversion.

关键词： biomass conversion mesoporous zeolite sustainable chemistry

Fast nuclear-spin gates and electrons−nuclei entanglement of neutral atoms in weak magnetic fields

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Frontiers of physics 2024年第2期19卷 179-203页

作者： xiao-feng Shi School of Physics Xidian UniversityXi’an 710071China

We present a novel class of Rydberg-mediated nuclear-spin entanglement in divalent atoms with global laser ***,we show a fast nuclear-spin controlled phase gate of an arbitrary phase realizable either with two laser pulses when assisted by Stark shifts,or with three ***,we propose to create an electrons−nuclei-entangled state,which is named a super bell state(SBS)for it mimics a large Bell state incorporating three small Bell ***,we show a protocol to create a three-atom electrons-nuclei entangled state which contains the three-body W and Greenberger−Horne−Zeilinger(GHZ)states *** protocols possess high intrinsic fidelities,do not require single-site Rydberg addressing,and can be executed with large Rydberg Rabi frequencies in a weak,Gauss-scale magnetic *** latter two protocols can enable measurement-based preparation of Bell,hyperentangled,and GHZ states,and,specifically,SBS can enable quantum dense coding where one can share three classical bits of information by sending one particle.

关键词： nuclear-spin qubit electrons−nuclei entanglement super Bell state Greenberger−Horne−Zeilinger state Rydberg-mediated entanglement quantum dense coding

Stereoselectiveα-Glycosylation with GlcN_(3)Donors Enabled Collective Syntheses of Acinetobacter baumannii Capsular Polysaccharides K43,K47 and K88 Repeating Units

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Chinese Journal of Chemistry 2024年第14期42卷 1593-1598页

作者： Kunxiu shou Shanshan Liu Yunqin Zhang Guozhi xiao State Key Laboratory of Phytochemistry and Plant Resources in West China Kunming Institute of BotanyUniversity of Chinese Academy of SciencesChinese Academy of SciencesKunmingYunnan650201 China

Collective syntheses of *** CPS K43,K47 and K88 repeating units have been accomplished via a newα-glycosylation method with GlcN_(3) as donors,which features:1)mild reaction conditions,2)good to high yields,3)excellent *** synthetic route also highlights an orthogonal one-pot coupling strategy on the basis of glycosyl ortho-(1-phenylvinyl)benzoates for stereoselective constructions of both 1,2-trans and 1,2-cis glycosidic bonds,precluding the issues of aglycone transfer.

关键词： A baumanni CPS α-Glycosylation method One-pot glycosylation 1,2-GlcN bonds Glycosyl ortho-(1-phenylvinyl)benzoates Carbohydrates Oligosaccharides Total synthesis

Advances in emission control of diesel vehicles in China

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Journal of Environmental Sciences 2023年第1期123卷 15-29页

作者： Guangyan Xu Wenpo Shan Yunbo Yu Yulong Shan xiaodong Wu Ye Wu Shaojun Zhang Liqiang He Shijin Shuai Hailong Pang Xuefeng Jiang Heng Zhang Lei Guo Shufen Wang feng-shou xiao Xiangju Meng feng Wu Dongwei Yao Yan Ding Hang Yin Hong He Research Center for Eco-Environmental Sciences Chinese Academy of SciencesBeijing 100085China Institute of Urban Environment Chinese Academy of SciencesXiamen 361021China Tsinghua University Beijing 100084China Army Military Transportation University Tianjin 300161China Dongfeng Motor Corporation Wuhan 430101China China National Heavy Duty Truck Group Company Limited Jinan 250000China Zhejiang University Hangzhou 310027China Chinese Research Academy of Environmental Sciences Beijing 100012China

Diesel vehicles have caused serious environmental problems in ***,the Chinese government has launched serious actions against air pollution and imposed more stringent regulations on diesel vehicle emissions in the latest China VI *** fulfill this stringent legislation,two major technical routes,including the exhaust gas recirculation(EGR)and high-efficiency selective catalytic reduction(SCR)routes,have been developed for diesel ***,complicated aftertreatment technologies have also been developed,including use of a diesel oxidation catalyst(DOC)for controlling carbon monoxide(CO)and hydrocarbon(HC)emissions,diesel particulate filter(DPF)for particle mass(PM)emission control,SCR for the control of NOx emission,and an ammonia slip catalyst(ASC)for the control of unreacted *** to the stringent requirements of the China VI standard,the aftertreatment system needs to be more deeply integrated with the engine *** the future,aftertreatment technologies will need further upgrades to fulfill the requirements of the near-zero emission target for diesel vehicles.

关键词： Diesel vehicles Legislation Emission control Aftertreatment system Nitrogen oxides Particulate matter

Contributors to tidal duration asymmetry with varied coastline configurations on western shelf of Yellow Sea

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Water Science and Engineering 2024年第1期17卷 1-12页

作者： Xi feng Zheng Li Hui feng Jia-yan Yang shou-peng Xie Wei-bing feng College of Harbor.Coastal and Offshore Engineering Hohai UniversityNanjing 210098China China Harbour Engineering Co. LtdBeijing 100027China Key Laboratory of Port Waterway and Sedimentation Engineering of the Ministry of CommunicationsNanjing 210029China China South-to-North Water Diversion Corporation Limited Beijing 100036China

Coastal management in China is confronted with an urgent choice between natural restoration and maintenance of existing seawalls and reclaimed land for economic development.A key criterion for making this decision is the resilience to coastal flooding,which depends on the ability to predict tidal *** duration asymmetry(TDA)is a key parameter in determination of the arrival and duration of flood *** study selected the western inner shelf of the Yellow Sea(WYS)as the study area and investigated the responses of TDA to different shoreline configurations and relative sea level *** responses of TDA to shoreline reconstruction yielded spatial variability locally and *** the nearshore area,the responses of TDA to the complex ocean environment mainly originated from the combined functions of reflection,bottom friction,and advection,which controlled the energy transfer from M2 or S2 constituents to their overtides or compound *** sensitivity of TDA to coastline typologies was not limited to coastal waters but could stretch over the entire inner *** vulnerability of tidal responses was due to the displacement of the M2 amphidrome of the Kelvin wave on the WYS,which in turn changed tidal energy fluxes over the *** relative sea level rise could intensify the feedback of TDA to seawalls and land reclamation.

关键词： Tidal duration asymmetry Western inner shelf of Yellow Sea Natural restoration Relative sea level rise Tidal amphidrome