乏燃料后处理废气中的放射性氙(Xe)和氪(Kr)的捕集和分离是核燃料循环的重要一环。固体吸附分离法在室温条件下实现氙与氪的分离更有效率,具有诸多优点,而高性能的吸附材料是该方法的关键。本文通过直接碳化ZIF-7前驱体的方法制备了MOF...乏燃料后处理废气中的放射性氙(Xe)和氪(Kr)的捕集和分离是核燃料循环的重要一环。固体吸附分离法在室温条件下实现氙与氪的分离更有效率,具有诸多优点,而高性能的吸附材料是该方法的关键。本文通过直接碳化ZIF-7前驱体的方法制备了MOF衍生的微孔碳材料Z7CB-1000。298 K及100 k Pa条件下Z7CB-1000对Xe的静态吸附容量为3.72 mmol·g-1,亨利系数为69.6 mmol·g-1·bar,Xe/Kr亨利选择性为19.1;穿透实验结果表明,298 K及100 k Pa条件下Z7CB-1000对Xe的动态吸附容量为17.6 mmol·kg-1,表明Z7CB-1000是一种有潜力的Xe吸附分离孔材料,可望用于核燃料循环中废气中Xe的捕集与分离。展开更多
先后采用化学浸渍和还原的方法制备了不同比例的沸石咪唑酯骨架材料ZIF-7负载CoB的催化剂,对其结构进行了表征,并系统探究了该催化剂在催化硼氢化钠水解制氢中的催化活性。结果表明,相比于纳米CoB粉末催化剂,负载型CoB/ZIF-7催化剂在硼...先后采用化学浸渍和还原的方法制备了不同比例的沸石咪唑酯骨架材料ZIF-7负载CoB的催化剂,对其结构进行了表征,并系统探究了该催化剂在催化硼氢化钠水解制氢中的催化活性。结果表明,相比于纳米CoB粉末催化剂,负载型CoB/ZIF-7催化剂在硼氢化钠水解制氢中具有更高的催化活性,25℃时NaBH_4水解产氢速率大约为252.19 m L/(min·g)。化学反应动力学表明:负载型CoB/ZIF-7催化剂催化NaBH_4水解制氢反应属于一级反应,其表观活化能约为51.48 k J/mol,远远低于纳米CoB粉末催化剂的活化能72.01 k J/mol。展开更多
The notorious"shuttle effect"of polysulfide during charge-discharge process induces grievous capacity fading,while the sluggish polysulfide conversion kinetics significantly hinders the development of practi...The notorious"shuttle effect"of polysulfide during charge-discharge process induces grievous capacity fading,while the sluggish polysulfide conversion kinetics significantly hinders the development of practically viable lithium-sulfur(Li-S)batteries.In this study,a novel ZIF-7@carbon composite with ZIF-7 sheets vertically rooted on carbon cloth was developed as multifunctional interlayer to address these issues.The composite shows directional layered structure with outstanding compactness,and thus can provide massive active sites for accelerated redox reactions.The pore channels are perpendicular to the square surface,resulting in extremely high utilization of one-dimensional channels.Therefore,this structure can not only maintain the structural stability during the charge-discharge process by providing enough space for volume expansion,but also contribute to efficient exposure and utilization of active sites for the physical/chemical adsorption and catalytic conversion of polysulfide.As a result,Li-S batteries with the as-developed interlayer deliver a considerable areal capacity of 4.75 mAh cm^(-2) at an elevated sulfur loading of 5.5 mg cm^(-2),and an impressive cyclability with an extremely low capacity-fading rate of merely 0.04%per cycle over 500 cycles at 1 C.展开更多
Porous ZIF-7 with the sodalite （SOD） cage structure （ZIF, Zeolitic imidazolate framework） were synthesized by the solvothermal method. Synthesized material was characterized by powder X-ray diffraction （PXRD）, t...Porous ZIF-7 with the sodalite （SOD） cage structure （ZIF, Zeolitic imidazolate framework） were synthesized by the solvothermal method. Synthesized material was characterized by powder X-ray diffraction （PXRD）, thermal gravity （TG）, scanning electron micro- scopy （SEM） and Na adsorption analysis. ZIF-8 with the SOD structure and a littl larger pore window was synthesized in a similar way and was characterized for comparisons. Thermal stability and structural stability of ZIF-7 were tested through PXRD analysis, and the capability of the material for CO2 capture from simulated flue gas was investigated through physical adsorption method. The results showed that CO： adsorption capacity on ZIF-7 was about 48 mL. gl while the capacity on ZIF-8 was about 18mg.g-1 （at 12C and 0.98 P/Po relative pressure）. Furthermore, the impact of flue gas components on adsorption capacity of ZIF-7 and the selectivity of CO2 against N2 on ZIF-7 was also investigated in this work展开更多
文摘乏燃料后处理废气中的放射性氙(Xe)和氪(Kr)的捕集和分离是核燃料循环的重要一环。固体吸附分离法在室温条件下实现氙与氪的分离更有效率,具有诸多优点,而高性能的吸附材料是该方法的关键。本文通过直接碳化ZIF-7前驱体的方法制备了MOF衍生的微孔碳材料Z7CB-1000。298 K及100 k Pa条件下Z7CB-1000对Xe的静态吸附容量为3.72 mmol·g-1,亨利系数为69.6 mmol·g-1·bar,Xe/Kr亨利选择性为19.1;穿透实验结果表明,298 K及100 k Pa条件下Z7CB-1000对Xe的动态吸附容量为17.6 mmol·kg-1,表明Z7CB-1000是一种有潜力的Xe吸附分离孔材料,可望用于核燃料循环中废气中Xe的捕集与分离。
文摘先后采用化学浸渍和还原的方法制备了不同比例的沸石咪唑酯骨架材料ZIF-7负载CoB的催化剂,对其结构进行了表征,并系统探究了该催化剂在催化硼氢化钠水解制氢中的催化活性。结果表明,相比于纳米CoB粉末催化剂,负载型CoB/ZIF-7催化剂在硼氢化钠水解制氢中具有更高的催化活性,25℃时NaBH_4水解产氢速率大约为252.19 m L/(min·g)。化学反应动力学表明:负载型CoB/ZIF-7催化剂催化NaBH_4水解制氢反应属于一级反应,其表观活化能约为51.48 k J/mol,远远低于纳米CoB粉末催化剂的活化能72.01 k J/mol。
基金the financial support from the Outstanding Young Talents Project of Hebei High Education Institutions(BJ2019013)the Natural Science Foundation of Hebei Province(B2019202289,B2019202199)+1 种基金the National Natural Science Foundation of China(No.21908039)the “Hundred Talents Program”of Hebei Province(E2019050013)。
文摘The notorious"shuttle effect"of polysulfide during charge-discharge process induces grievous capacity fading,while the sluggish polysulfide conversion kinetics significantly hinders the development of practically viable lithium-sulfur(Li-S)batteries.In this study,a novel ZIF-7@carbon composite with ZIF-7 sheets vertically rooted on carbon cloth was developed as multifunctional interlayer to address these issues.The composite shows directional layered structure with outstanding compactness,and thus can provide massive active sites for accelerated redox reactions.The pore channels are perpendicular to the square surface,resulting in extremely high utilization of one-dimensional channels.Therefore,this structure can not only maintain the structural stability during the charge-discharge process by providing enough space for volume expansion,but also contribute to efficient exposure and utilization of active sites for the physical/chemical adsorption and catalytic conversion of polysulfide.As a result,Li-S batteries with the as-developed interlayer deliver a considerable areal capacity of 4.75 mAh cm^(-2) at an elevated sulfur loading of 5.5 mg cm^(-2),and an impressive cyclability with an extremely low capacity-fading rate of merely 0.04%per cycle over 500 cycles at 1 C.
文摘Porous ZIF-7 with the sodalite （SOD） cage structure （ZIF, Zeolitic imidazolate framework） were synthesized by the solvothermal method. Synthesized material was characterized by powder X-ray diffraction （PXRD）, thermal gravity （TG）, scanning electron micro- scopy （SEM） and Na adsorption analysis. ZIF-8 with the SOD structure and a littl larger pore window was synthesized in a similar way and was characterized for comparisons. Thermal stability and structural stability of ZIF-7 were tested through PXRD analysis, and the capability of the material for CO2 capture from simulated flue gas was investigated through physical adsorption method. The results showed that CO： adsorption capacity on ZIF-7 was about 48 mL. gl while the capacity on ZIF-8 was about 18mg.g-1 （at 12C and 0.98 P/Po relative pressure）. Furthermore, the impact of flue gas components on adsorption capacity of ZIF-7 and the selectivity of CO2 against N2 on ZIF-7 was also investigated in this work
