In order to explore the effect mechanism of solvent on the synthesis of the metal organic framework materials, the microscopic interaction between solvent and framework and the effects of N,N-dimethyl-formamide(DMF) o...In order to explore the effect mechanism of solvent on the synthesis of the metal organic framework materials, the microscopic interaction between solvent and framework and the effects of N,N-dimethyl-formamide(DMF) or N-methyl- 2-pyrrolidone(NMP) on solvothermal synthesis of [Zn4O(BDC)3]8 were investigated through a combined DFT and experimental study. XRD and SEM showed that the absorbability of NMP in the pore of [Zn4O(BDC)3]8 was weaker than that of DMF. The thermal decomposition temperature of [Zn4O(BDC)3]8 synthesized in DMF was higher than that in NMP according to TG and FT-IR. In addition, the nitrogen sorption isotherms indicated that NMP improved gas sorption property of [Zn4O(BDC)3]8. The COSMO optimized calculations indicated that the total energy of Zn4O(BDC)3 in NMP was higher than that in DMF, and compared with non-solvent system, the charge of zinc atoms decreased and the charge value was the smallest in NMP. Furthermore, the interaction of DMF, NMP or DEF in [Zn4O(BDC)3]8 crystal model was calculated by DFT method. The results suggested that NMP should be easier to be removed from pore of materials than DMF from the point of view of energy state. It can be concluded that NMP was a favorable solvent to synthesize [Zn4O(BDC)3]8 and the microscopic mechanism was that the binding force between Zn4O(BDC)3 and NMP molecule was weaker than DMF.展开更多
Lithium carbon dioxide(Li-CO_(2))batteries deliver a theoretical energy density of 1876 W h kg^(-1) in terms of effective utilization of greenhouse gases.This battery system is considered to be an encouraging electroc...Lithium carbon dioxide(Li-CO_(2))batteries deliver a theoretical energy density of 1876 W h kg^(-1) in terms of effective utilization of greenhouse gases.This battery system is considered to be an encouraging electrochemical energy storage device and a promising alternative to Li-ion batteries.However,the main drawback of Li-CO_(2) batteries is their accumulative discharge product of Li_(2)CO_(3)/C,which leads to large overpotential and poor cycling performance.Thus,specific and efficient catalysts must be explored to enhance the decomposition of Li_(2)CO_(3)/C.Single-atom catalysts(SACs)are regarded as promising heterogeneous catalysts owing to their maximized utilization of metal atoms and strong interfacial electronic interactions.Herein,single-metal atoms of Fe,Co,and Ni uniformly anchored on N-doped reduced graphene oxide(rGO),designated as Fe_(1)/N-rGO,Co1/N-rGO,and Ni_(1)/N-r GO,respectively,are designed and fabricated to investigate their catalytic activity toward the decomposition of Li_(2)CO_(3)/C.Among them,Fe_(1)/N-rGO delivers a high discharge capacity of 16,835 mA h g^(-1) at 100 mA g^(-1) and maintains stability for more than 170 cycles with a discharge voltage of 2.30 V at 400 mA g^(-1).Therefore,this catalysts are overwhelmingly superior to other types.This work reveals the advances of SACs in Li-CO_(2) batteries and offers an effective method for realizing high-performance Li-CO_(2) batteries.展开更多
基金Project(51104185)supported by the National Natural Science Foundation of ChinaProject(2010QZZD003)supported by the Key Project of Central South University of Fundamental Research Funds for the Central Universities of China
文摘In order to explore the effect mechanism of solvent on the synthesis of the metal organic framework materials, the microscopic interaction between solvent and framework and the effects of N,N-dimethyl-formamide(DMF) or N-methyl- 2-pyrrolidone(NMP) on solvothermal synthesis of [Zn4O(BDC)3]8 were investigated through a combined DFT and experimental study. XRD and SEM showed that the absorbability of NMP in the pore of [Zn4O(BDC)3]8 was weaker than that of DMF. The thermal decomposition temperature of [Zn4O(BDC)3]8 synthesized in DMF was higher than that in NMP according to TG and FT-IR. In addition, the nitrogen sorption isotherms indicated that NMP improved gas sorption property of [Zn4O(BDC)3]8. The COSMO optimized calculations indicated that the total energy of Zn4O(BDC)3 in NMP was higher than that in DMF, and compared with non-solvent system, the charge of zinc atoms decreased and the charge value was the smallest in NMP. Furthermore, the interaction of DMF, NMP or DEF in [Zn4O(BDC)3]8 crystal model was calculated by DFT method. The results suggested that NMP should be easier to be removed from pore of materials than DMF from the point of view of energy state. It can be concluded that NMP was a favorable solvent to synthesize [Zn4O(BDC)3]8 and the microscopic mechanism was that the binding force between Zn4O(BDC)3 and NMP molecule was weaker than DMF.
基金supported by the National Natural Science Foundation of China (52034011)the Key R&D Program of Shaanxi (2019ZDLGY04-05)+2 种基金the National Natural Science Foundation of Shaanxi (2020JQ-189, 2019JLM-29 and 2019JLZ-01)the Fundamental Research Funds for the Central Universities (G2020KY05129)the Research Fund of the State Key Laboratory of Solidification Processing (NPU),China (2020-BJ-03 and 2019-TS-06)
文摘Lithium carbon dioxide(Li-CO_(2))batteries deliver a theoretical energy density of 1876 W h kg^(-1) in terms of effective utilization of greenhouse gases.This battery system is considered to be an encouraging electrochemical energy storage device and a promising alternative to Li-ion batteries.However,the main drawback of Li-CO_(2) batteries is their accumulative discharge product of Li_(2)CO_(3)/C,which leads to large overpotential and poor cycling performance.Thus,specific and efficient catalysts must be explored to enhance the decomposition of Li_(2)CO_(3)/C.Single-atom catalysts(SACs)are regarded as promising heterogeneous catalysts owing to their maximized utilization of metal atoms and strong interfacial electronic interactions.Herein,single-metal atoms of Fe,Co,and Ni uniformly anchored on N-doped reduced graphene oxide(rGO),designated as Fe_(1)/N-rGO,Co1/N-rGO,and Ni_(1)/N-r GO,respectively,are designed and fabricated to investigate their catalytic activity toward the decomposition of Li_(2)CO_(3)/C.Among them,Fe_(1)/N-rGO delivers a high discharge capacity of 16,835 mA h g^(-1) at 100 mA g^(-1) and maintains stability for more than 170 cycles with a discharge voltage of 2.30 V at 400 mA g^(-1).Therefore,this catalysts are overwhelmingly superior to other types.This work reveals the advances of SACs in Li-CO_(2) batteries and offers an effective method for realizing high-performance Li-CO_(2) batteries.
