We report a new facile light-induced strategy to disperse micron-sized aggregated bulk covalent organic frameworks(COFs)into isolated COFs nanoparticles.This was achieved by a series of metal-coordinated COFs,namely C...We report a new facile light-induced strategy to disperse micron-sized aggregated bulk covalent organic frameworks(COFs)into isolated COFs nanoparticles.This was achieved by a series of metal-coordinated COFs,namely COF-909-Cu,-Co or-Fe,where for the first time the diffusio-phoretic propulsion was utilized to design COF-based micro/nanomotors.The mechanism studies revealed that the metal ions decorated in the COF-909 backbone could promote the separation of electron and holes and trigger the production of sufficient ionic and reactive oxygen species under visible light irradiation.In this way,strong light-induced self-diffusiophoretic effect is achieved,resulting in good dispersion of COFs.Among them,COF-909-Fe showed the highest dispersion performance,along with a drastic decrease in particle size from 5μm to500 nm,within only 30 min light irradiation,which is inaccessible by using traditional magnetic stirring or ultrasonication methods.More importantly,benefiting from the outstanding dispersion efficiency,COF-909-Fe micro/nanomotors were demonstrated to be efficient in photocatalytic degradation of tetracycline,about 8 times faster than using traditional magnetic stirring method.This work opens up a new avenue to prepare isolated nanosized COFs in a high-fast,simple,and green manner.展开更多
Precise modulation of the structure and composition of electrocatalysts is critical for promoting the kinetically sluggish process of oxygen reduction reaction(ORR)and oxygen evolution reaction(OER).Covalent organic f...Precise modulation of the structure and composition of electrocatalysts is critical for promoting the kinetically sluggish process of oxygen reduction reaction(ORR)and oxygen evolution reaction(OER).Covalent organic frameworks(COF)offer a novel way to create highly efficient electrocatalysts due to their tunable composition,structure and surface area.Herein,we report a high-efficiency bifunctional electrocatalyst comprising Co nanoparticles embedded within N-doped carbons(Co@NCs)for Zn-air batteries(ZABs).The Co@NC is yielded via the coordination of a triazine COF with Co-containing precursors and subsequent calcination under inert atmosphere.The as-prepared Co@NC exhibits remarkable ORR/OER performance and great potential in rechargeable ZABs.The liquid ZAB constructed with Co@NC provides both high specific capacity and power density.Remarkably,the ZAB exhibits a voltage gap of 0.8 V during discharge and charge cycles and high stability for 220 h compared to the Pt/C-assembled battery.This strategy for regulating electrocatalytic activities of COF-derived carbon materials could be expanded for creating various carbon catalysts.展开更多
Industrial growth in recent years led to air pollution and an increase in concentration of hazardous gases such as O<sub>3</sub> and NO. Developing new materials is important to detect and reduce air pollu...Industrial growth in recent years led to air pollution and an increase in concentration of hazardous gases such as O<sub>3</sub> and NO. Developing new materials is important to detect and reduce air pollutants. While catalytic decomposition and zeolites are traditional ways used to reduce the amount of these gases. We need to develop and explore new promising materials. Covalent organic framework (COF) has become an attractive platform for researcher due to its extended robust covalent bonds, porosity, and crystallinity. In this study, first principal calculations were performed for gases adsorption using COFs containing nitrogen and π-bonds. Different building blocks (BBs) and linkers (LINKs/LINK1 & LINK2) were investigated by means of density functional theory (DFT) calculations with B3LYP and 3-21G basis sets to calculate the binding energies of gases @COF systems. Electrostatic potential maps (ESPM), Mulliken charges and non-covalent interaction (NCI) are used to understand the type of interactions between gas and COFs fragments. O3 was found to bind strongly with COF system in comparison with NO which could make COF a useful selective material for mixed gases environment for sensing and removal application.展开更多
The ice exceeding one million years old has significant meaning for verifying and interpreting the middle Pleistocene transition （MPT） and the relationship between greenhouse gas and climate change. The region near ...The ice exceeding one million years old has significant meaning for verifying and interpreting the middle Pleistocene transition （MPT） and the relationship between greenhouse gas and climate change. The region near Dome A in Antarctica satisfies the conditions for obtaining million-years-old ice since it has low temperatures and low accumulation rates. We analyze the corresponding relation between radar wave features and the crystal orientation fabric （COF） types based on the results of multi-polarization plane radio echo sounding （RES）. The results show that, even in the summit of the ice sheet, the COF type is not perfect, but is an elongated single-pole COF. Principal-axis-orientation differences of the COF among the different periods exist and reveal that the ice flow orientations are not constant but deviate clockwise with the increasing depth. This may be related to the adjacent basal valley or both height and position changes of the summit during the glacial-interglacial periods.展开更多
基金supported by Huazhong University of Science and Technology(No.2021XXJS036,3004013134)National Natural Science Foundation of China(No.51903099,82002879,22102059)+2 种基金the Innovation and Talent Recruitment Base of New Energy Chemistry and Device(No.B21003)China Postdoctoral Science Foundation(2021M692475,2021T140524,XJ2021037)support from the 100 Talents Program of the Hubei Provincial Government。
文摘We report a new facile light-induced strategy to disperse micron-sized aggregated bulk covalent organic frameworks(COFs)into isolated COFs nanoparticles.This was achieved by a series of metal-coordinated COFs,namely COF-909-Cu,-Co or-Fe,where for the first time the diffusio-phoretic propulsion was utilized to design COF-based micro/nanomotors.The mechanism studies revealed that the metal ions decorated in the COF-909 backbone could promote the separation of electron and holes and trigger the production of sufficient ionic and reactive oxygen species under visible light irradiation.In this way,strong light-induced self-diffusiophoretic effect is achieved,resulting in good dispersion of COFs.Among them,COF-909-Fe showed the highest dispersion performance,along with a drastic decrease in particle size from 5μm to500 nm,within only 30 min light irradiation,which is inaccessible by using traditional magnetic stirring or ultrasonication methods.More importantly,benefiting from the outstanding dispersion efficiency,COF-909-Fe micro/nanomotors were demonstrated to be efficient in photocatalytic degradation of tetracycline,about 8 times faster than using traditional magnetic stirring method.This work opens up a new avenue to prepare isolated nanosized COFs in a high-fast,simple,and green manner.
基金supported by the Natural Science Foundation of Shandong Province(ZR2019PB013)the Training Program of Innovation and Entrepreneurship for Undergraduates of Liaocheng University(CXCY2022277)。
文摘Precise modulation of the structure and composition of electrocatalysts is critical for promoting the kinetically sluggish process of oxygen reduction reaction(ORR)and oxygen evolution reaction(OER).Covalent organic frameworks(COF)offer a novel way to create highly efficient electrocatalysts due to their tunable composition,structure and surface area.Herein,we report a high-efficiency bifunctional electrocatalyst comprising Co nanoparticles embedded within N-doped carbons(Co@NCs)for Zn-air batteries(ZABs).The Co@NC is yielded via the coordination of a triazine COF with Co-containing precursors and subsequent calcination under inert atmosphere.The as-prepared Co@NC exhibits remarkable ORR/OER performance and great potential in rechargeable ZABs.The liquid ZAB constructed with Co@NC provides both high specific capacity and power density.Remarkably,the ZAB exhibits a voltage gap of 0.8 V during discharge and charge cycles and high stability for 220 h compared to the Pt/C-assembled battery.This strategy for regulating electrocatalytic activities of COF-derived carbon materials could be expanded for creating various carbon catalysts.
文摘Industrial growth in recent years led to air pollution and an increase in concentration of hazardous gases such as O<sub>3</sub> and NO. Developing new materials is important to detect and reduce air pollutants. While catalytic decomposition and zeolites are traditional ways used to reduce the amount of these gases. We need to develop and explore new promising materials. Covalent organic framework (COF) has become an attractive platform for researcher due to its extended robust covalent bonds, porosity, and crystallinity. In this study, first principal calculations were performed for gases adsorption using COFs containing nitrogen and π-bonds. Different building blocks (BBs) and linkers (LINKs/LINK1 & LINK2) were investigated by means of density functional theory (DFT) calculations with B3LYP and 3-21G basis sets to calculate the binding energies of gases @COF systems. Electrostatic potential maps (ESPM), Mulliken charges and non-covalent interaction (NCI) are used to understand the type of interactions between gas and COFs fragments. O3 was found to bind strongly with COF system in comparison with NO which could make COF a useful selective material for mixed gases environment for sensing and removal application.
基金the National Natural Science Foundation of China(Grant No.40874060)the 863 projection(Grant No.2006AA09Z152)
文摘The ice exceeding one million years old has significant meaning for verifying and interpreting the middle Pleistocene transition （MPT） and the relationship between greenhouse gas and climate change. The region near Dome A in Antarctica satisfies the conditions for obtaining million-years-old ice since it has low temperatures and low accumulation rates. We analyze the corresponding relation between radar wave features and the crystal orientation fabric （COF） types based on the results of multi-polarization plane radio echo sounding （RES）. The results show that, even in the summit of the ice sheet, the COF type is not perfect, but is an elongated single-pole COF. Principal-axis-orientation differences of the COF among the different periods exist and reveal that the ice flow orientations are not constant but deviate clockwise with the increasing depth. This may be related to the adjacent basal valley or both height and position changes of the summit during the glacial-interglacial periods.
