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Atomically dispersed calcium as solid strong base catalyst with high activity and stability

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Green Energy & Environment 2024年第10期9卷 1619-1626页

作者： Xiang-Bin Shao Zhi-Wei Xing Si-Yu Liu Ke-Xin Miao shi-chao qi Song-Song Peng Xiao-qin Liu Lin-Bing Sun State Key Laboratory of Materials-Oriented Chemical Engineering Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM)College of Chemical EngineeringNanjing Tech University30 South Puzhu Road

Solid strong base catalysts are highly attractive for diverse reactions owing to their advantages of neglectable corrosion,facile separation,and environmental ***,their widespread applications are impeded by basic components aggregation and low *** this work,we fabricate single calcium atoms on graphene （denoted as Ca1/G） by use of a redox strategy for the first time,producing solid strong base catalyst with high activity and *** precursor Ca（NO3）2is first reduced to CaO at 400℃ by the support graphene,forming CaO/G with conventional basic sites,and the subsequent reduction at 850℃ results in the generation of Ca1/G with atomically dispersed *** characterizations reveal that Ca single atoms are anchored on graphene in tetra-coordination （Ca–C2–N2） where N is in situ doped from Ca（NO3）*** atomically dispersed Ca,along with their anchoring on the support,endow Ca1/G with high activity and stability toward the transesterification reaction of ethylene carbonate with *** turnover frequency value reaches 128.0 h-1on Ca1/G,which is much higher than the traditional counterpart CaO/G and various reported solid strong bases (2.9–46.2 h-1).Moreover,the activity of Ca1/G is well maintained during 5 cycles,while 60% of activity is lost for the conventional analogue CaO/G due to the leaching of Ca.

关键词： Solid strong base Single Ca atoms Heterogeneous catalysts Transesterification Reaction

Graphene-anchored sodium single atoms:A highly active and stable catalyst for transesterification reaction

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Nano Research 2024年第6期17卷 4979-4985页

作者： Song-Song Peng Yao Nian Xing-Ru Song Xiang-Bin Shao Chen Gu Zhi-Wei Xing shi-chao qi Peng Tan You Han Xiao-qin Liu Lin-Bing Sun State Key Laboratory of Materials-Oriented Chemical Engineering Jiangsu National Synergetic Innovation Center for Advanced Materials(SICAM)College of Chemical EngineeringNanjing Tech University30 South Puzhu RoadNanjing 211816China School of Chemical Engineering and Technology Tianjin UniversityTianjin 300072China Haihe Laboratory of Sustainable Chemical Transformations Tianjin 300192China

Solid strong base catalysts have received considerable attention in various organic reactions due to their facile separation,neglectable corrosion,and environmental *** great progress has been made in the preparation of solid strong base catalysts,it is still challenging to avoid basic sites aggregation on support and active sites loss in reaction ***,we report a tandem redox strategy to prepare Na single atoms on graphene,producing a new kind of solid strong base catalyst(Na1/G).The base precursor NaNO_(3)was first reduced to Na2O by graphene(400℃)and successively to single atoms Na anchored on the graphene vacancies(800℃).Owing to the atomically dispersed of basicity,the resultant catalyst presents high activity toward the transesterification of methanol and ethylene carbonate to synthesize dimethyl carbonate(turnover frequency(TOF)value:125.7 h^(−1)),which is much better than the conventional counterpart Na2O/G and various reported solid strong bases(TOF:1.0-90.1 h^(−1)).Furthermore,thanks to the basicity anchored on graphene,the Na1/G catalyst shows excellent durability during *** work may provide a new direction for the development of solid strong base catalysts.

关键词： solid strong base catalyst basic sites redox graphene single Na atoms

Fabrication of azobenzene-functionalized porous polymers for selective CO_(2) capture

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Chinese Journal of Chemical Engineering 2022年第3期35卷 24-30页

作者： Ding-Ming Xue Wen-Juan Zhang Xiao-qin Liu shi-chao qi Lin-Bing Sun State Key Laboratory of Materials-Oriented Chemical Engineering Jiangsu National Synergetic Innovation Center for Advanced Materials(SICAM)College of Chemical EngineeringNanjing Tech UniversityNanjing 211816China

Many solid adsorbents have been prepared for the CO_(2)*** particular,the photoresponsive adsorbents have attracted extensive interests because of their tunable pore structure and variable responsive behaviors provoked by the external ***,it is challenging to fabricate the photoresponsive adsorbents featured the big CO_(2)capacity and high CO_(2)***,copolymerized between 4-phenylazobenzoyl chloride,2,4,6-trichloro-1,3,5-triazine and melamine,a series of azobenzenefunctionalized porous polymers(PTM-AZOs)are successfully *** PTM-AZOs are verified in possession of proper pore structures,large surface area and photoconductive properties through a series of *** PTM-AZO-2 with the trans-isomerization exhibits the best CO_(2)adsorption amount of 2.7 mmol·g^(-1)(273 K and 0.1 MPa),while the CO_(2)/N_(2)selectivity can reach 2459 and 607 on the trans-and cis-isomerization,*** regulatable pore structures controlled by the photoresponsive azobenzene groups affect the CO_(2)capture performance of the PTM-AZOs.

关键词： Adsorption CO_(2)capture Selectivity Azobenzene Photoresponse

Photo-switchable Cu^(+)sites in metal-organic frameworks for adsorptive desulfurization

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Nano Research 2023年第2期16卷 3333-3338页

作者： Yu-Yang Gu Guoliang Liu shi-chao qi Chen Gu Tao Yang Xiao-qin Liu Lin-Bing Sun State Key Laboratory of Materials-Oriented Chemical Engineering Jiangsu National Synergetic Innovation Center for Advanced Material(SICAM)College of Chemical EngineeringNanjing Tech UniversityNanjing 211816China

Photo-switchable metal-organic frameworks(PMOFs)as energy-saving adsorbents for tailorable guest capture show admirable potentials for various applications like adsorptive ***,the regulation behavior of most reported PMOFs is based on weak physical interaction,and it is highly desired to introduce specific active sites to satisfy the demand of higher adsorption capacity and ***,for the first time,we prepared the PMOFs,azobenzene-functionalized HKUST-1(HK-Azo),simultaneously decorated with Cu_(2)O active sites that possess strong interaction with guest *** toπ-complexation interaction of Cu^(+)with aromatic sulfur compounds,the obtained HK-Azo shows obviously higher adsorption capacity on benzothiophene compared with *** ultraviolet(UV)and visible irradiation,azobenzene moieties in the PMOFs can transform their configuration freely and *** trans/cis isomerization of azobenzene causes exposure/shelter of Cu_(2)O active sites,leading to controllable benzothiophene *** HK-Azo exhibits the change of benzothiophene uptake up to 29.7%upon trans and cis isomerization,which is obviously higher than HKUST-1 with negligible *** work may inspire the development of new adsorption process regulated by light for adsorptive desulfurization that is impossible to realize by conventional PMOFs.

关键词： Cu+active sites metal-organic frameworks photo-switchable property azobenzene adsorptive desulfurization

Implementing an“Impracticable”Copolymerization to Fabricate a Desired Polymer Precursor for N-doped Porous Carbons

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Engineering 2022年第9期16卷 154-161页

作者： shi-chao qi Xiao-Jie Lu Yin-Cong Lou Rui Zhou Ding-Ming Xue Xiao-qin Liu Lin-Bing Sun State Key Laboratory of Materials-Oriented Chemical Engineering Jiangsu National Synergetic Innovation Center for Advanced Material(SICAM)College of Chemical EngineeringNanjing Tech UniversityNanjing 211816China

It is common that a proof-of-concept of a desired reaction,which might generate materials with new functions or application potential,is eventually proved impracticable or commercially *** efforts have been made but wasted in searching for unknown reaction conditions in solvent environments because it was believed that the activity of reactants can be enhanced to facilitate reactions by dissolving them in ***,an abnormal case was discovered in this study.A desired copolymerization reaction between 1,3,5-tris(chloromethyl)-2,4,6-trimethylbenzene and melamine was confirmed to be impracticable under various solvent conditions;however,it was successfully implemented using a solvent-free *** first-principle calculations and molecular dynamics simulations,two decisive factors that the reaction in solvents cannot possess,namely the reaction equilibrium being pushed by the timely release of by-products and the confined thermal motions of the activated monomer molecules in the solid phase,were demonstrated to make the copolymerization successful in the solvent-free *** to the high aromaticity and azacyclo-content,the as-synthetic copolymer exhibited good application potential as a precursor to fabricate N-doped porous carbons with satisfactory carbon yields,ideal N contents,desired textural properties,and competitive CO_(2)capture abilities compared to other representative counterparts reported recently.

关键词： Solvent-free method Solvent effect Copolymerization N-doped porous carbon

An antiempirical strategy:sacrificing aromatic moieties in the polymer precursor for improving the properties of the derived N-doped porous carbons

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Green Chemical Engineering 2020年第1期1卷 70-76页

作者： shi-chao qi Ding-Ming Xue Guo-Xing Yu Rong-Rong Zhu Xiao-qin Liu Lin-Bing Sun State Key Laboratory of Materials-Oriented Chemical Engineering Jiangsu National Synergetic Innovation Center for Advanced Material(SICAM)College of Chemical EngineeringNanjing Tech UniversityNanjing211816China

With the carbonization at an elevated temperature,high aromaticity of a precursor for porous carbons was traditionally thought to be crucial for the resultant perfect textural properties and ideal application performances of the porous ***,many efforts have been done to search or to artificially prepare the polymer precursors with higher aromaticity to generate more satisfying porous ***,an antiempirical case was found in this *** copolymerization between 1,3,5-tris(chloromethyl)-2,4,6-trimethylbenzene(TCM)and cyclohexane-1,4-diamine was successfully implemented to get a polymer code-named NUT-40,in which half of the ring structures are nonaromatic,while N-doped porous carbons(NDPCs)with better textural properties(e.g.,SBET=1363 m^(2)g^(-1)for NDPC-600)and competitive CO_(2)capture abilities(e.g.,CO_(2)capacity=4.3 mmol g^(-1)at 25℃and 1 bar for NDPC-600)were generated from the NUT-40,compared with the NDPC counterparts derived from the NUT-4 in a previous study(e.g.,SBET=958 m^(2)g^(-1)and CO_(2)capacity=3.8 mmol g^(-1)at 25℃and 1 bar for NDPC-600),in which TCM and ursol were employed as the monomers instead,and thus the ring structures in the NUT-4 was fully *** first-principle and molecular dynamics simulations,it was demonstrated that the embryo pore structure in the NUT-40 molecule can be more easily maintained during the carbonization than that of the NUT-4,which finally improves the surface area and porosity of the NUT-40 generated NDPCs.

关键词： Copolymer Aromaticity Pyrolysis Carbon capture N-doped porous carbon

A Review on Engineering Design for Enhancing Interfacial Contact in Solid-State Lithium–Sulfur Batteries

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Nano-Micro Letters 2024年第4期16卷 219-252页

作者： Bingxin qi Xinyue Hong Ying Jiang Jing shi Mingrui Zhang Wen Yan chao Lai School of Chemistry and Materials Science Jiangsu Normal UniversityXuzhou 221116JiangsuPeople’s Republic of China

The utilization of solid-state electrolytes(SSEs)presents a promising solution to the issues of safety concern and shuttle effect in Li–S batteries,which has garnered significant interest ***,the high interfacial impedances existing between the SSEs and the electrodes(both lithium anodes and sulfur cathodes)hinder the charge transfer and intensify the uneven deposition of lithium,which ultimately result in insufficient capacity utilization and poor cycling ***,the reduction of interfacial resistance between SSEs and electrodes is of paramount importance in the pursuit of efficacious solid-state *** this review,we focus on the experimental strategies employed to enhance the interfacial contact between SSEs and electrodes,and summarize recent progresses of their applications in solidstate Li–S ***,the challenges and perspectives of rational interfacial design in practical solid-state Li–S batteries are outlined as *** expect that this review will provide new insights into the further technique development and practical applications of solid-state lithium batteries.

关键词： Solid-state lithium–sulfur batteries Solid-state electrolytes Electrode/electrolyte interface Interfacial engineering Enhancing interfacial contact

Adverse effect of niobium and boron on hot deformation behavior of sulfur-containing steel

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Journal of Iron and Steel Research International 2024年第1期31卷 252-263页

作者： Guo-ning He shi-qi Wan Bo Jiang chao-lei Zhang Ya-zheng Liu Chun-jing Wu School of Materials Science and Engineering University of Science and Technology BeijingBeijing100083China Institute for Advanced Materials and Technology University of Science and Technology BeijingBeijing100083China

The hot deformation behaviors of sulfur-containing gear steel 20MnCr5 containing three different contents of Nb and B(0,0.021%Nb,and 0.024%Nb-0.0022%B)were *** compression and tenssion tests were carried out by Gleeble3800 at the austenite region from 850 to 1150℃and the adverse effects of Nb and B were analyzed by the fracture,microstructure and precipitate *** compression tests showed that the proportions of instable area in hot processing maps of 0.021%Nb and Nb-B steels were higher and the deformability of Nb free steel was *** tensile deformation experiments showed that the reduction areas of Nb free,0.021%Nb and Nb-B steels were 92%-99%,84%-98%and 67%-97%,*** addition of Nb or Nb and B inhibited the dynamic recrystallization during hot deformation,and consequently,more deformed grains were then formed in 0.021%Nb and Nb-B steels thus to obtain the microstructure with worse uniformity and then deteriorate the *** addition,the interaction between inclusions and microalloyed elements was also *** particles of 0.021%Nb and Nb-B steels dynamically precipitated during deformation and precipitated together with MnS thus to worsen the deformability,resulting in the decrease of reduction area.

关键词： Hot deformation Gear steel Processing map Dynamic recrystallization Microalloying

Dynamic Scene Graph Generation of Point Clouds with Structural Representation Learning

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Tsinghua Science and Technology 2024年第1期29卷 232-243页

作者： chao qi Jianqin Yin Zhicheng Zhang Jin Tang School of Artificial Intelligence Beijing University of Posts and TelecommunicationsBeijing 100876China Standard and Metrology Research Institute China Academy of Railway Sciences Corporation LimitedBeijing 100081China

Scene graphs of point clouds help to understand object-level relationships in the 3D *** graph generation methods work on 2D structured data,which cannot be used for the 3D unstructured point cloud *** point-cloud-based methods generate the scene graph with an additional graph structure that needs labor-intensive manual *** address these problems,we explore a method to convert the point clouds into structured data and generate graphs without given ***,we cluster points with similar augmented features into groups and establish their relationships,resulting in an initial structural representation of the point ***,we propose a Dynamic Graph Generation Network(DGGN)to judge the semantic labels of targets of different *** dynamically splits and merges point groups,resulting in a scene graph with high *** show that our methods outperform other baseline *** output reliable graphs describing the object-level relationships without additional manual labeled data.

关键词： scene graph generation structural representation point cloud