Metal-organic frameworks(MOFs)have been intensely studied for the past few decades as an enormous family of highly tunable porous materials with promisingly applicable functionalities in adsorption,separation,catalysi...Metal-organic frameworks(MOFs)have been intensely studied for the past few decades as an enormous family of highly tunable porous materials with promisingly applicable functionalities in adsorption,separation,catalysis,sensing,electrochemistry,and a great number of emerging purposes.As a classic MOF,zeolitic imidazolate framework-8(ZIF-8)is conventionally one of the very few MOF members that has been commercialized with considerable production.展开更多
The feasibility of adsorption and the adsorption behavior of radon on a nanomaterial-based zeolitic imidazolate framework-8(ZIF-8) adsorbent were investigated.Grand canonical Monte Carlo simulation and four-channel lo...The feasibility of adsorption and the adsorption behavior of radon on a nanomaterial-based zeolitic imidazolate framework-8(ZIF-8) adsorbent were investigated.Grand canonical Monte Carlo simulation and four-channel low-background a/b measurement were performed to examine the adsorption kinetics of this adsorbent. Results demonstrated that ZIF-8 is a good adsorbent of radon.Therefore, this adsorbent can be used to significantly reduce the hazardous effects of radon on occupational radiation workers.展开更多
Zeolitic imidazolate framework-8(ZIF-8)with porous structure,biocompatibility,and pH-sensitive release behavior is a promising nanoplatform for protein delivery.However,it is still a challenging task for a practical s...Zeolitic imidazolate framework-8(ZIF-8)with porous structure,biocompatibility,and pH-sensitive release behavior is a promising nanoplatform for protein delivery.However,it is still a challenging task for a practical synthesis of protein-loaded ZIF-8 nanoparticles.Here we report an all-aqueous microfluidic reactor for one-step,rapid,and highly controlled synthesis of ZIF-8 nanoparticles with high protein loading at room temperature.Microfluidic reactor allows for an ultrafast(<35 ms),complete mixing of Zn2+ions and 2-methylimidazole(2-MIM)at different molecular ratios,leading to the formation of stable ZIF-8 nanoparticles with tunable sizes(13.2–191.4 nm)in less than 30 s.By pre-mixing various proteins such as bovine serum albumin(BSA)(isoelectric point(pI)=5.82),ovalbumin(OVA)(pI=4.82),or RNase A(pI=8.93)with 2-MIM,ZIF-8 nanoparticles can be synthesized with protein encapsulation efficiency over 97%.Among the nanoparticles with different sizes,25 nm ZIF-8 nanoparticles show the best performance in promoting the cellular uptake of protein payload.Using OVA as a model protein,we demonstrate that 25 nm ZIF-8 nanoparticles significantly enhance the cytosolic delivery of antigen,as indicated by the effective activation of dendritic cells.We anticipate that this microfluidic synthesis of nanomaterials may advance the emerging field of cytosolic protein delivery.展开更多
设计了高产率胺基化ZIF-8的合成、表征及其储存CH_(4)性能综合实验。综合考虑增大倍数、反应釜容积、合成温度和时间,确定高产率ZIF-8的合成工艺,采用5.732 g Zn(NO_(3))_(2)·6H_(2)O与4.748 g的2-甲基咪唑混合加入113 mL的DMF溶液...设计了高产率胺基化ZIF-8的合成、表征及其储存CH_(4)性能综合实验。综合考虑增大倍数、反应釜容积、合成温度和时间,确定高产率ZIF-8的合成工艺,采用5.732 g Zn(NO_(3))_(2)·6H_(2)O与4.748 g的2-甲基咪唑混合加入113 mL的DMF溶液中,在160℃的恒温干燥箱中加热24 h。以此为基础,合成得到ZIF-8-NH_(2)。与ZIF-8相比,ZIF-8-NH_(2)具有更高的CH_(4)储量、较低的再生能耗和较好的循环使用性能。实验内容涉及多孔材料合成、高产率材料合成工艺、微观结构表征及气体吸附储存性能评价等多方面知识,改变了传统的天然气储存与利用课程中讲授为主的教学模式,加深了学生对理论知识的理解,锻炼学生动手能力,提高学生的综合素质和科研创新能力。展开更多
商业化LiFePO_4(LFP)正极材料的导电性一直是制约其性能提高的关键。为了提高LFP的性能,利用沸石咪唑酯骨架-8(ZIF-8)制备多孔碳材料(CZIF-8)改善商业化LFP正极材料的导电性,对比了两种改性LFP的方法:1)将退火的ZIF-8以物理混合的方法与...商业化LiFePO_4(LFP)正极材料的导电性一直是制约其性能提高的关键。为了提高LFP的性能,利用沸石咪唑酯骨架-8(ZIF-8)制备多孔碳材料(CZIF-8)改善商业化LFP正极材料的导电性,对比了两种改性LFP的方法:1)将退火的ZIF-8以物理混合的方法与LFP混合制得LFP/CZIF-8正极材料;2)ZIF-8在LFP表面原位生长后退火制得LFP@CZIF-8正极材料。X射线粉末衍射(XRD)、氮气吸脱附(BET)和拉曼光谱等测试证明,改性后的LFP仍具有橄榄石型结构,同时出现了具有介孔结构的石墨化碳材料的特征。扫描电子显微镜(SEM)和透射电子显微镜(TEM)测试证明LFP/CZIF-8样品中LFP与CZIF-8之间未形成链接结构,而在LFP@CZIF-8样品中二者形成了核壳结构。电化学阻抗测试(EIS)表明,改性后样品的离子传输阻抗明显减小,说明两种方法均提高了LFP的导电性。充放电循环测试表明,两种改性方法均能提高LFP的循环性能和库伦效率。不同的是,倍率性能测试表明,LFP/CZIF-8样品的高倍率性能比LFP@CZIF-8样品更有优势,在10.0 C电流倍率下能够达到57.8 m A·h/g。这一研究为商业化锂离子电池电极材料的改性提供了新的思路,并且通过方法优化为产业化做了铺垫。展开更多
The requirement of energy-storage equipment needs to develop the lithium ion battery(LIB) with high electrochemical performance. The surface modification of commercial LiFePO_4(LFP) by utilizing zeolitic imidazolate f...The requirement of energy-storage equipment needs to develop the lithium ion battery(LIB) with high electrochemical performance. The surface modification of commercial LiFePO_4(LFP) by utilizing zeolitic imidazolate frameworks-8(ZIF-8) offers new possibilities for commercial LFP with high electrochemical performances.In this work, the carbonized ZIF-8(C_(ZIF-8)) was coated on the surface of LFP particles by the in situ growth and carbonization of ZIF-8. Transmission electron microscopy indicates that there is an approximate 10 nm coating layer with metal zinc and graphite-like carbon on the surface of LFP/C_(ZIF-8) sample. The N_2 adsorption and desorptionisotherm suggests that the coating layer has uniform and simple connecting mesopores. As cathode material, LFP/C_(ZIF-8) cathode-active material delivers a discharge specific capacity of 159.3 m Ah g^(-1) at 0.1 C and a discharge specific energy of 141.7 m Wh g^(-1) after 200 cycles at 5.0 C(the retention rate is approximate 99%). These results are attributed to the synergy improvement of the conductivity,the lithium ion diffusion coefficient, and the degree of freedom for volume change of LFP/C_(ZIF-8) cathode. This work will contribute to the improvement of the cathode materials of commercial LIB.展开更多
Fe-N-C endowed with inexpensiveness,high activity,and excellent anti-poisoning power have emerged as promising candidate catalysts for oxygen reduction reaction(ORR).Single-atom Fe-N-C electrocatalysts derived from Fe...Fe-N-C endowed with inexpensiveness,high activity,and excellent anti-poisoning power have emerged as promising candidate catalysts for oxygen reduction reaction(ORR).Single-atom Fe-N-C electrocatalysts derived from Fe-doped ZIF-8 represent the top-level ORR performance.However,the current fabrication of Fe-doped ZIF-8 relies on heavy consumption of time,energy,cost and organic solvents.Herein,we develop a rapid and solvent-free method to produce Fe-doped ZIF-8 under microwave irradiation,which can be easily amplified in combination with ball-milling.After rational pyrolysis,Fe-N-C catalysts with atomic FeN4 sites well dispersed on the hierarchically porous carbon matrix are obtained,which exhibit exceptional ORR performance with a half-wave potential of 0.782 V(vs.reversible hydrogen electrode(RHE))and brilliant methanol tolerance.The assembled direct methanol fuel cells(DMFCs)endow a peak power density of 61 mW cm^(-2) and extraordinary stability,highlighting the application perspective of this strategy.展开更多
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.51603052 and 51573216)the Fundamental Research Funds for the Central Universities(Grant Nos.18lgpy02 and 16lgjc66).
文摘Metal-organic frameworks(MOFs)have been intensely studied for the past few decades as an enormous family of highly tunable porous materials with promisingly applicable functionalities in adsorption,separation,catalysis,sensing,electrochemistry,and a great number of emerging purposes.As a classic MOF,zeolitic imidazolate framework-8(ZIF-8)is conventionally one of the very few MOF members that has been commercialized with considerable production.
基金Supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)the Open Project of Jiangsu Provincial Key Laboratory of Radiation Medicine and Protection(No.KJS1246)
文摘The feasibility of adsorption and the adsorption behavior of radon on a nanomaterial-based zeolitic imidazolate framework-8(ZIF-8) adsorbent were investigated.Grand canonical Monte Carlo simulation and four-channel low-background a/b measurement were performed to examine the adsorption kinetics of this adsorbent. Results demonstrated that ZIF-8 is a good adsorbent of radon.Therefore, this adsorbent can be used to significantly reduce the hazardous effects of radon on occupational radiation workers.
基金supported by the National Key R&D Program of China(Nos.2020YFA0210800 and 2021YFA0909400)the National Natural Science Foundation of China(Nos.22025402,22227805,T2222008,and 22174030)+1 种基金The Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB36020300)CAS Project for Young Scientists in Basic Research(No.YSBR-036).
文摘Zeolitic imidazolate framework-8(ZIF-8)with porous structure,biocompatibility,and pH-sensitive release behavior is a promising nanoplatform for protein delivery.However,it is still a challenging task for a practical synthesis of protein-loaded ZIF-8 nanoparticles.Here we report an all-aqueous microfluidic reactor for one-step,rapid,and highly controlled synthesis of ZIF-8 nanoparticles with high protein loading at room temperature.Microfluidic reactor allows for an ultrafast(<35 ms),complete mixing of Zn2+ions and 2-methylimidazole(2-MIM)at different molecular ratios,leading to the formation of stable ZIF-8 nanoparticles with tunable sizes(13.2–191.4 nm)in less than 30 s.By pre-mixing various proteins such as bovine serum albumin(BSA)(isoelectric point(pI)=5.82),ovalbumin(OVA)(pI=4.82),or RNase A(pI=8.93)with 2-MIM,ZIF-8 nanoparticles can be synthesized with protein encapsulation efficiency over 97%.Among the nanoparticles with different sizes,25 nm ZIF-8 nanoparticles show the best performance in promoting the cellular uptake of protein payload.Using OVA as a model protein,we demonstrate that 25 nm ZIF-8 nanoparticles significantly enhance the cytosolic delivery of antigen,as indicated by the effective activation of dendritic cells.We anticipate that this microfluidic synthesis of nanomaterials may advance the emerging field of cytosolic protein delivery.
文摘商业化LiFePO_4(LFP)正极材料的导电性一直是制约其性能提高的关键。为了提高LFP的性能,利用沸石咪唑酯骨架-8(ZIF-8)制备多孔碳材料(CZIF-8)改善商业化LFP正极材料的导电性,对比了两种改性LFP的方法:1)将退火的ZIF-8以物理混合的方法与LFP混合制得LFP/CZIF-8正极材料;2)ZIF-8在LFP表面原位生长后退火制得LFP@CZIF-8正极材料。X射线粉末衍射(XRD)、氮气吸脱附(BET)和拉曼光谱等测试证明,改性后的LFP仍具有橄榄石型结构,同时出现了具有介孔结构的石墨化碳材料的特征。扫描电子显微镜(SEM)和透射电子显微镜(TEM)测试证明LFP/CZIF-8样品中LFP与CZIF-8之间未形成链接结构,而在LFP@CZIF-8样品中二者形成了核壳结构。电化学阻抗测试(EIS)表明,改性后样品的离子传输阻抗明显减小,说明两种方法均提高了LFP的导电性。充放电循环测试表明,两种改性方法均能提高LFP的循环性能和库伦效率。不同的是,倍率性能测试表明,LFP/CZIF-8样品的高倍率性能比LFP@CZIF-8样品更有优势,在10.0 C电流倍率下能够达到57.8 m A·h/g。这一研究为商业化锂离子电池电极材料的改性提供了新的思路,并且通过方法优化为产业化做了铺垫。
基金supported by the Scientific and Technological Development Project of the Beijing Education Committee(No.KZ201710005009)
文摘The requirement of energy-storage equipment needs to develop the lithium ion battery(LIB) with high electrochemical performance. The surface modification of commercial LiFePO_4(LFP) by utilizing zeolitic imidazolate frameworks-8(ZIF-8) offers new possibilities for commercial LFP with high electrochemical performances.In this work, the carbonized ZIF-8(C_(ZIF-8)) was coated on the surface of LFP particles by the in situ growth and carbonization of ZIF-8. Transmission electron microscopy indicates that there is an approximate 10 nm coating layer with metal zinc and graphite-like carbon on the surface of LFP/C_(ZIF-8) sample. The N_2 adsorption and desorptionisotherm suggests that the coating layer has uniform and simple connecting mesopores. As cathode material, LFP/C_(ZIF-8) cathode-active material delivers a discharge specific capacity of 159.3 m Ah g^(-1) at 0.1 C and a discharge specific energy of 141.7 m Wh g^(-1) after 200 cycles at 5.0 C(the retention rate is approximate 99%). These results are attributed to the synergy improvement of the conductivity,the lithium ion diffusion coefficient, and the degree of freedom for volume change of LFP/C_(ZIF-8) cathode. This work will contribute to the improvement of the cathode materials of commercial LIB.
基金financially supported by the Key Program of the Chinese Academy of Sciences(KFZD-SW-419),Chinathe Major Research Plan of the National Natural Science Foundation of China(91834301),China。
文摘Fe-N-C endowed with inexpensiveness,high activity,and excellent anti-poisoning power have emerged as promising candidate catalysts for oxygen reduction reaction(ORR).Single-atom Fe-N-C electrocatalysts derived from Fe-doped ZIF-8 represent the top-level ORR performance.However,the current fabrication of Fe-doped ZIF-8 relies on heavy consumption of time,energy,cost and organic solvents.Herein,we develop a rapid and solvent-free method to produce Fe-doped ZIF-8 under microwave irradiation,which can be easily amplified in combination with ball-milling.After rational pyrolysis,Fe-N-C catalysts with atomic FeN4 sites well dispersed on the hierarchically porous carbon matrix are obtained,which exhibit exceptional ORR performance with a half-wave potential of 0.782 V(vs.reversible hydrogen electrode(RHE))and brilliant methanol tolerance.The assembled direct methanol fuel cells(DMFCs)endow a peak power density of 61 mW cm^(-2) and extraordinary stability,highlighting the application perspective of this strategy.
