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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

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 RoadNanjing211816China

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(NO_(3))_(2)is 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-C_(2)-N_(2))where N is in situ doped from Ca(NO_(3))_(2).The 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^(-1)on 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

Breathing Metal-Organic Polyhedra Controlled by Light for Carbon Dioxide Capture and Liberation

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CCS Chemistry 2021年第6期3卷 1659-1668页

作者： Yao Jiang Peng Tan Shi-Chao Qi Chen Gu Song-Song Peng Fan Wu Xiao-Qin Liu lin-bing sun State Key Laboratory of Materials-Oriented Chemical Engineering College of Chemical EngineeringNanjing Tech UniversityNanjing 211816

Metal-organic polyhedra(MOPs)have emerged as versatile platforms for artificial models of biological systems due to their discrete structure and modular ***,the design and fabrication of MOPs with special functionality for mimicking biological processes are *** by the breathing mechanism of lungs,we developed a new type of MOP(a breathing MOP,denoted as NUT-101)by directly using azobenzene units as the pillars of the polyhedra to coordinate with Zr-based metal *** addition to considerable thermal and chemical stability,the obtained MOP exhibits photocontrollable breathing *** irradiation with visible or UV light,the configuration of azobenzene units transforms,leading to reversible expansion or contraction of the cages and,correspondingly,capture or liberation of CO_(2)*** a breathing behavior of NUT-101 is further confirmed by density functional theory(DFT)*** system might establish an avenue for the construction of new materials with particular functionality that mimic biological processes.

关键词： metal-organic polyhedra breathing photoresponsive systems adsorbents carbon dioxide capture

Ce-Doped Smart Adsorbentswith Photoresponsive Molecular Switches for Selective Adsorption and Efficient Desorption

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Engineering 2020年第5期6卷 569-576页

作者： Peng Tan Yao Jiang Shi-Chao Qi Xia-Jun Gao Xiao-Qin Liu lin-bing sun State Key Laboratory of Materials-Oriented Chemical Engineering Jiangsu National Synergetic Innovation Center for Advanced MaterialsCollege of Chemical EngineeringNanjing Tech UniversityNanjing 211816China

Achieving efficient adsorption and desorption processes by controllably tuning the properties of adsorbents at different technical stages is extremely ***,it is difficult for traditional adsorbents to reach the target because of their fixed active ***,we report on the fabrication of a smart adsorbent,which was achieved by introducing photoresponsive azobenzene derivatives with cis/trans isomers to Ce-doped mesoporous *** photoresponsive groups serve as “molecular switches”by sheltering and exposing active sites,leading to efficient adsorption and *** is also doped to provide additional active sites in order to enhance the adsorption *** results show that the cis isomers effectively shelter the active sites,leading to the selective adsorption of methylene blue(MB)over brilliant blue(BB),while the trans isomers completely expose the active sites,resulting in the convenient release of the *** selective adsorption and efficient desorption can be realized controllably by these smart adsorbents through ***,the performance of the obtained materials is well maintained after five cycles.

关键词： Azobenzene Ce-doped mesoporous silica Molecular switches Selective adsorption Efficient desorption

Generating strongly basic sites on magnetic nano-stirring bars:Multifunctional integrated catalysts for transesterification reaction

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Science China Materials 2022年第10期65卷 2721-2728页

作者： Chen Gu Tian-Tian Li Peng Tan Song-Song Peng Yao Jiang 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 UniversityNanjing 211816China

Mass transfer and catalyst recovery are two crucial issues in solid base catalysis,while the cumbersome operation steps and the associated time and energy penalties are still inevitable for conventional *** the technical upgrades through catalyst design is desirable but challenging because of the difficulty in satisfying diverse demands of different *** this work,a magnetically responsive solid base catalyst with the rod-like nanostructure was *** rod-like solid base catalysts are composed of Fe_(3)O_(4) cores,silica shells and calcium oxide active *** functions of magnetic recovery and stirring were integrated into the catalyst,which applies in both the general catalytic processes and microchannel reactors given their *** applied to the synthesis of dimethyl carbonate by onestep transesterification of methanol and ethylene carbonate,an apparent enhancement on turnover frequency value(33.1 h^(−1))was observed for nano-stirring compared with that tested without stirring(12.1 h^(−1))within 30 *** present catalysts may open up new avenues in the development of advanced solid base catalysts.

关键词： magnetic responsiveness nano-stirring bars dimethyl carbonate solid base catalyst

Smart adsorbents for CO2 capture:Making strong adsorption sites respond to visible light

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Science China Materials 2021年第2期64卷 383-392页

作者： Qiu-Rong Wu Peng Tan Chen Gu Rui Zhou Shi-Chao Qi Xiao-Qin Liu Yao Jiang lin-bing sun State Key Laboratory of Materials-Oriented Chemical Engineering Jiangsu National Synergetic Innovation Center for Advanced MaterialsCollege of Chemical EngineeringNanjing Tech UniversityNanjing211816China

Due to the good controllability and high energy efficiency in adsorption processes,photoresponsive adsorbents are intriguing for CO2 ***,most reported photoresponsive adsorbents are designed based on weak adsorption sites,regulating CO2 adsorption through structural change or steric *** addition,ultraviolet(UV)light is commonly involved in the regulation of adsorption *** we report for the first time the smart adsorbents for CO2 capture,which makes strong adsorption sites respond to visible(Vis)*** adsorbents were fabricated by introducing primary amine and Dispersed Red 1(DR1,a kind of push-pull azobenzene that responds to Vis light rapidly)units to mesoporous silica,which act as strong adsorption sites and triggers,*** primary amine sites make the adsorbents highly selective in the adsorption of CO2 over *** light irradiation,azobenzene is in the form of trans configuration,which leads to decreased electrostatic potential of primary amines and subsequently,exposure of active sites and liberal adsorption of *** Vis-light irradiation,cis isomers are formed,which results in increased electrostatic potential of primary amines and subsequently shelter of active *** on such strong adsorption sites,the alteration of CO2 adsorption capacity can reach 40%for the adsorbent with and without Vis-light ***,the trans/cis isomerization of DR1 units can be triggered reversibly by Vis *** present smart system endows adsorbents with selective adsorption capacity and avoids the employment of UV light,which is unlikely to be achieved by conventional photoresponsive adsorbents.

关键词： CO2 adsorption strong adsorption sites selective adsorption push-pull azobenzene visible light response

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转子碰摩波内调制特征提取及其故障诊断应用

电子测量与仪器学报 2021年第2期35卷 94-100页

作者：刘小峰张池柏林孙兵重庆大学机械传动国家重点实验室重庆400044

为深入分析不同转静碰摩故障引起振动响应信号波内调制特征的变化规律,以Jeffcott转子模型为基础,采用基于变分模态分解的Hilbert变换方法对不同碰摩故障仿真信号进行波内调制特征的提取与分析,揭示了碰摩转子的动力学特性与其故障信号... 详细信息

为深入分析不同转静碰摩故障引起振动响应信号波内调制特征的变化规律,以Jeffcott转子模型为基础,采用基于变分模态分解的Hilbert变换方法对不同碰摩故障仿真信号进行波内调制特征的提取与分析,揭示了碰摩转子的动力学特性与其故障信号波内调制特性间的关联机理。仿真结果表明,周期-k碰摩故障将导致振动响应信号中低频段波内调频模态的瞬时频率以1/k倍频为中心振荡,且振荡频率依然为1/k倍频,进而造成了频谱中的1/k边频带;在概周期碰摩故障中,波内调制频率为靠近1/k倍频的无理数倍频和整数倍频,且造成振动信号频谱中的无理数边频带。离心泵转子故障诊断试验表明,波内调制特征能够有效地对转子碰摩故障进行有效的诊断。

关键词：转子碰摩变分模态分解波内调频瞬时频率