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Probing deactivation by coking in catalyst pellets for dry reforming of methane using a pore network model

Chinese Journal of Chemical engineering 2023年第3期55卷 293-303页

作者： Yu Wang Qunfeng Zhang Xinlei Liu Junqi Weng Guanghua Ye Xinggui Zhou State Key Laboratory of Chemical Engineering School of Chemical EngineeringEast China University of Science and TechnologyShanghai 200237China

Dry reforming of methane(DRM) is an attractive technology for utilizing the greenhouse gases(CO_(2) and CH_(4)) to produce syngas. However, the catalyst pellets for DRM are heavily plagued by deactivation by coking, which prevents this technology from commercialization. In this work, a pore network model is developed to probe the catalyst deactivation by coking in a Ni/Al_(2)O_(3) catalyst pellet for DRM. The reaction conditions can significantly change the coking rate and then affect the catalyst deactivation. The catalyst lifetime is higher under lower temperature, pressure, and CH_(4)/CO_(2) molar ratio, but the maximum coke content in a catalyst pellet is independent of these reaction conditions. The catalyst pellet with larger pore diameter, narrower pore size distribution and higher pore connectivity is more robust against catalyst deactivation by coking, as the pores in this pellet are more difficult to be plugged or *** maximum coke content is also higher for narrower pore size distribution and higher pore connectivity, as the number of inaccessible pores is lower. Besides, the catalyst pellet radius only slightly affects the coke content, although the diffusion limitation increases with the pellet radius. These results should serve to guide the rational design of robust DRM catalyst pellets against deactivation by coking.

关键词： Deactivation by coking Dry reforming of methane Pore network model Diffusion limitation Catalyst pellet

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Self-sustaining alkaline seawater electrolysis via forward osmosis membranes

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Green Energy & Environment 2025年第3期10卷 518-527页

作者： Ke Shi Hongyi Wan keyu Wang Fumohan Fang Shiyi Li Yixing Wang Linfeng Lei Linzhou Zhuang Zhi Xu State Key Laboratory of Chemical Engineering East China University of Science and TechnologyShanghai200237China Suzhou Laboratory Suzhou215000China Department of Chemistry and Chemical Engineering Hunan Institute of Science and TechnologyYueyangHunanYueyang414000China

Seawater electrolysis for hydrogen production faces inherent challenges, including side reactions, corrosion, and scaling, stemming from the intricate composition of seawater. In response, researchers have turned to continuous water splitting using forward osmosis(FO)-driven seawater desalination. However, the necessity of a neutral electrolyte hampers this strategy due to the limited current density and scarcity of precious metals. Herein, this study applies alkali-durable FO membranes to enable self-sustaining seawater splitting, which can selectively withdraw water molecules, from seawater, via concentration gradient. The membranes demonstrates outstanding perm-selectivity of water/ions(~5830 mol mol^(-1)) during month-long alkaline resistance tests, preventing electrolyte leaching(>97% OHàretention) while maintaining ~95%water balance(V_(FO)= V_(electrolysis)) via preserved concentration gradient for consistent forward-osmosis influx of water molecules. With the consistent electrolyte environment protected by the polyamide FO membranes, the Ni Fe-Ar-P catalyst exhibits promising performance: a sustain current density of 360 m A cmà2maintained at the cell voltage of 2.10 V and 2.15 V for 360 h in the offshore seawater, preventing Cl/Br corrosion(98% rejection) and Mg/Ca passivation(99.6% rejection). This research marks a significant advancement towards efficient and durable seawater-based hydrogen production.

关键词： Alkaline water electrolysis Forward osmosis Self-sustaining seawater splitting Hydrogen evolution Real seawater

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Stereoscopic Imaging of Single Molecules at Plasma Membrane of Single Cell Using Photoreduction-Assisted Electrochemistry

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Research 2025年第1期7卷 975-983页

作者： Rong Jin Yu Li Yanyan Xu Lei Cheng Dechen Jiang State Key Laboratory of Analytical Chemistry for Life Science and School of Chemistry and Chemical Engineering Nanjing UniversityNanjingChina College of Engineering and Technology Southwest UniversityChongqingChina

Stereoscopic imaging of single molecules at the plasma membrane of single cell requires spatial resolutions in 3 dimensions(x-y-z)at 10-nm level,which is rarely achieved using most optical super-resolution ***,electrochemical stereoscopic microscopy with a detection limit down to a single molecule is achieved using a photoreduction-assisted cycle inside a 20-nm gel electrolyte nanoball at the tip of a *** the basis of the electrochemical oxidation of Ru(bpy)_(3)^(2+)into Ru(bpy)33+followed by the reduction of Ru(bpy)_(3)^(3+)into Ru(bpy)_(3)^(2+)by photogenerated isopropanol radicals,a charge of 1.5 fC is obtained from the cycling electron transfers involving one Ru(bpy)_(3)^(2+/3+)*** using the nanopipette to scan the cellular membrane modified with Ru(bpy)_(3)^(2+)-tagged antibody,the morphology of the cell membrane and the distribution of carcinoembryonic antigen(CEA)on the membrane are electrochemically visualized with a spatial resolution of 14 *** resultant stereoscopic image reveals more CEA on membrane protrusions,providing direct evidence to support easy access of membrane CEA to intravenous *** breakthrough in single-molecule electrochemistry at the cellular level leads to the establishment of high-resolution 3-dimensional single-cell electrochemical microscopy,offering an alternative strategy to remedy the imperfection of stereoscopic visualization in optical microscopes.

关键词： stereoscopic imaging electrochemical oxidation plasma membrane photoreduction assisted electrochemistry single molecules stereoscopic microscopy

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Phthalocyanine-derived catalysts decorated by metallic nanoclusters for enhanced CO_(2)electroreduction

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Green Energy & Environment 2023年第2期8卷 444-451页

作者： Jiacheng Chen Jiayu Li Jing Xu Minghui Zhu Yi-Fan Han State Key Laboratory of Chemical Engineering School of Chemical EngineeringEast China University of Science and TechnologyShanghai200237China

Electrochemical CO_(2)reduction(CO_(2)RR)over molecular catalysts is a paramount approach for CO_(2)conversion to ***,we report a novel phthalocyanine-derived catalyst synthesized by a two-step method with a much improved ***,the catalyst contains both Ni-N4sites and highly dispersed metallic Ni nanoclusters,leading to an increased CO_(2)RR currents by two *** labelling study and in situ spectroscopic analysis demonstrate that the existence of metallic Ni nanoclusters is the key factor for the activity enhancement and can shift the CO_(2)RR mechanism from being electron transfer(ET)-limited(forming*COO^(-))to concerted proton-electron transfer(CPET)-limited(forming CO).

关键词： Carbon dioxide Electroreduction Hybrid catalyst Nickel-based catalysts Mechanism

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Mechanistic insights into the active intermediates of 2,6-diaminopyridine dinitration

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Chinese Journal of Chemical engineering 2023年第4期56卷 160-168页

作者： Junao Zhu Zhirong Yang Yuanhan Chen Mingming Chen Zhen Liu Yueqiang Cao Jing Zhang Gang Qian Xinggui Zhou Xuezhi Duan State Key Laboratory of Chemical Engineering School of Chemical EngineeringEast China University of Science and TechnologyShanghai 200237China

Mechanistic understanding of the active intermediates of 2,6-diaminopyridine(DAP) dinitration in the concentrated nitric-sulfuric acid system is of crucial importance for the selectivity control of target product, i.e., 2,6-diamino-3,5-dinitropyridine(DADNP). The active intermediates determining the product selectivity are theoretically studied. The HSO_(4)^(-)-NO_(2)^(+) complex is proposed as the dominant active nitrating intermediate for the first time, which shows low energy barrier(i.e., 10.19 kcal·mol^(-1),1 kcal = 4.186 k J) for direct dinitration of DAP to DADNP. The formed water during the reaction results in not only the formation of less active SO_(4)^(2-)-NO_(2)^(+) complex, but also the occurance of DAP sulfonation(DAP-SO_(3)H intermediate)to facilitate the formation of mononitration byproduct. Meanwhile, the accompanied thermal effects cause the generation of undesirable pyridine-NHNO_(2) intermediate, which is difficult to be rearranged to yield DADNP, inhibiting the reaction and thus giving low DAP conversion. The insights reported here elucidates the importance of thermal effects elimination and water content control, confirmed experimentally in the batch-and micro-reaction systems.

关键词： 2,6-Diaminopyridine Nitration mechanism Active intermediates Thermal effects Negative water effects

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A review of test methods for uniaxial compressive strength of rocks:Theory,apparatus and data processing

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Journal of Rock Mechanics and Geotechnical engineering 2025年第3期17卷 1889-1905页

作者： Wei-Qiang Xie Xiao-Li Liu Xiao-Ping Zhang Quan-Sheng Liu En-ZhiWang State Key Laboratory of Hydroscience and Engineering Tsinghua UniversityBeijing100084China Yunlong Lake Laboratory of Deep Underground Science and Engineering Xuzhou221000China The Key Laboratory of Safety for Geotechnical and Structural Engineering of Hubei Province School of Civil EngineeringWuhan UniversityWuhan430072China

The uniaxial compressive strength(UCS)of rocks is a vital geomechanical parameter widely used for rock mass classification,stability analysis,and engineering design in rock *** UCS testing methods and apparatuses have been proposed over the past few *** objective of the present study is to summarize the status and development in theories,test apparatuses,data processing of the existing testing methods for UCS *** starts with elaborating the theories of these test *** the test apparatus and development trends for UCS measurement are summarized,followed by a discussion on rock specimens for test apparatus,and data processing ***,the method selection for UCS measurement is *** reveals that the rock failure mechanism in the UCS testing methods can be divided into compression-shear,compression-tension,composite failure mode,and no obvious failure *** trends of these apparatuses are towards automation,digitization,precision,and multi-modal *** size correction methods are commonly *** is to develop empirical correlation between the measured indices and the specimen *** other is to use a standard specimen to calculate the size correction *** to five input parameters are commonly utilized in soft computation models to predict the UCS of *** selection of the test methods for the UCS measurement can be carried out according to the testing scenario and the specimen *** engineers can gain a comprehensive understanding of the UCS testing methods and its potential developments in various rock engineering endeavors.

关键词： Uniaxial compressive strength(UCS) UCS testing methods Test apparatus Data processing

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Polybenzoxazine/organosilicon composites with low dielectric constant and dielectric loss

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Chinese Journal of Chemical engineering 2023年第12期64卷 241-249页

作者： Manlin Yuan Xin Lu Xiaoyun Ma Hao Lin Angui Lu Liyan Shao Zhong Xin State Key Laboratory of Chemical Engineering School of Chemical EngineeringEast China University of Science and TechnologyShanghai 200237China

The evolution of electronic communication technology raises higher requirements for low dielectric constant(low-k)*** this,a benzoxazine functional organosilicon(HP-aptes)with dense Si—O—Si crosslinking networks and large sterically hindered tert-butyl groups was prepared by the sol–gel ***,a series of polybenzoxazine composites(PPHP)were prepared from intrinsically low dielectric constant bis-functional benzoxazine monomer(P-aptmds)and *** double crosslinking networks of polybenzoxazine and organosilicon further increased the crosslinking density and decreased the dipole density of composites,which endowed the composites with enhanced low-k *** the content of HP-aptes is 30%(mass),the crosslinking density was 2.05×10^(-3)mol·cm^(-3),while that of PP-aptmds was 3.31×10^(-3)mol·cm^(-3).In addition,the dielectric constant and dielectric loss of PPHP composite at 1 MHz could reach 2.61 and 0.0056,respectively.

关键词： Polybenzoxazine Organosilicon Composite Dielectric constant

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Deactivation and regeneration of the commercial Cu/ZnO/Al_(2)O_(3) catalyst in low-temperature methanol steam reforming

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science China Chemistry 2023年第12期66卷 3645-3652页

作者： Didi Li Zhen Wang Shiqing Jin Minghui Zhu State Key Laboratory of Chemical Engineering School of Chemical EngineeringEast China University of Science and TechnologyShanghai 200237China

Cu-based catalysts with excellent activity at low temperatures are widely used for methanol steam reforming(MSR)but suffer from deactivation *** present work aims to elucidate the deactivation and regeneration mechanisms of the commercial Cu/ZnO/Al_(2)O_(3) catalyst in low temperature *** employing a series of(quasi)in situ characterization methods,it is found that the deactivation of the catalyst at a high weight hourly space velocity(WHSV)and a low reaction temperature is mainly due to the poisoning of Cu species associated with surface-oxygenated species with less Cu sintering,rather than carbon deposition,and strong metal-support interaction(SMSI).An in situ regeneration method was developed for the deactivated commercial Cu/ZnO/Al_(2)O_(3) catalyst via the simultaneous supply of O_(2).It is shown that the addition of O_(2)(≥1 vol%)can reverse the deactivation caused by surface-oxygenated poisoning due to the weak interaction between formed surface copper oxide and surface-oxygenated species,facilitating their desorption,but not deactivation caused by sintering,thereby partially restoring the catalytic activity.

关键词： methanol steam reforming Cu/ZnO/Al_(2)O_(3)catalyst deactivation regeneration

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The Effect of In situ Melt Pre-shear Induced Oriented Precursors on the Crystallization of Poly(1-butene)/Polypropylene Blends

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Chinese Journal of Polymer science 2024年第12期42卷 2011-2020,I0012页

作者： Wen-Kang Wei Jing-Jing Zhao Chen-Guang Liu Dong Wang Ai-Hua He Shandong Provincial Key Laboratory of Olefin Catalysis and Polymerization Key Laboratory of Rubber-Plastics(Ministry of Education)School of Polymer Science and EngineeringQingdao University of Science and TechnologyQingdao266042China State Key Laboratory of Organic-Inorganic Composites Beijing University of Chemical TechnologyBeijing100029China

Melt pre-shear induced crystallization of polymer blends holds great significance in industrial processing and product *** this work,two typical PB/PP blends(50/50,90/10),possessing commercial value and academic hotspot,were employed to investigate the effect of melt pre-shear on the crystallization of isotactic poly(1-butene)(PB)and polypropylene(PP)by applying shearing slightly above the melting temperature of PP with subsequent non-isothermal crystallization to simulate actual processing *** was discovered that in PB/PP(90/10)blend,in situ melt pre-shear generated oriented PP precursors induced the formation of PP-FIC(Flow-induced crystallization)which acted as row crystal nucleus significantly promoting PB crystallization into spherulite with higher melting temperatures(T_(m)),crystallinity(X_(c)),and thicker lamellar thickness(d_(c)).While in PB/PP(50/50)blend,the melt pre-shear generated PP-shish precursors induced the formation of PP shish-kebab that exerted a confining effect on the crystal growth of PB,resulting in truncated spherulite formation with higher T_(m) and thicker d_(c) but lower X_(c).This research provides insight into the mechanism underlying oriented crystal structure formation,crystal properties,and phase morphology of PB/PP blends under melt pre-shear fields,which have significant theoretical and practical implications for their industrial processing and preparation of high-performance products.

关键词： Meltpre-shear PB/PPblends Precursors Crystallization

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Inner-pore reduction nucleation of palladium nanoparticles in highly conductive wurster-type covalent organic frameworks for efficient oxygen reduction electrocatalysis

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Journal of Energy Chemistry 2023年第2期77卷 543-552,I0014页

作者： Weiwen Wang Lu Zhang Tianping Wang Zhen Zhang Xiangnan Wang Chong Cheng Xikui Liu College of Polymer Science and Engineering State Key Laboratory of Polymer Materials EngineeringSichuan UniversityChengdu 610065SichuanChina

Covalent organic frameworks(COFs)have emerged as a class of promising supports for electrocatalysis because of their advantages including good crystallinity,highly ordered pores,and structural ***,their poor conductivity represents the main obstruction to their practical ***,we reported a novel synthesis strategy for synergistically endowing a triphenylamine-based COFs with improved electrical conductivity and excellent catalytic activity for oxygen reduction,via the in-situ redox deposition and confined growth of palladium nanoparticles inside the porous structure of COFs using reductive triphenylamine frameworks as reducing agent;meanwhile,the triphenylamine unit was oxidized to radical cation structure and affords radical cation COFs with conductivity as high as3.2*10^(-1) S m^(-1).Such a uniform confine palladium nanoparticle on highly conductive COFs makes it an efficient electrocatalyst for four-electron oxygen reduction reaction(4e-ORR),showing excellent activities and fast kinetics with a remarkable half-wave potential(E_(1/2))of 0.865 V and an ultralow Tafel slope of 39.7 mV dec^(-1) in alkaline media even in the absence of extra commercial conductive *** generality of this strategy was proved by preparing the different metal and metal alloy nanoparticles supported on COFs(Au@COF,Pt@COF,AuPd@COF,AgPd@COF,and PtPd@COF)using reductive triphenylamine frameworks as reducing *** work not only provides a facile strategy for the fabrication of highly conductive COF supported ORR electrocatalysts,but also sheds new light on the practical application of Zn-air battery.

关键词： Covalent organic frameworks Wurster-type structure In-situ reduction nucleation Palladium nanoparticles Oxygen reduction electrocatalysis

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