Hierarchical porous zeolitic imidazolate frameworks （ZIFs） have potential for adsorption, catalysis and chemical sensing applications. Ultrafast synthesis of ZIFs at room temperature and pressure is particularly des...Hierarchical porous zeolitic imidazolate frameworks （ZIFs） have potential for adsorption, catalysis and chemical sensing applications. Ultrafast synthesis of ZIFs at room temperature and pressure is particularly desirable for large-scale industrial production. Here, we developed a green and versatile method using organic amines as supramolecular templates （organic amine-template） to rapidly synthesize hierarchical porous ZIFs （ZIF-8, ZIF-61 and ZIF-90） at room temperature and pressure. The synthesis time was reduced dramatically to within 1 min, and the resulting ZIFs had multimodal hierarchical porous structures with mesopores/ macropores interconnected with micropores. Notably, the space-time yield （STY） of hierarchical porous ZIF-8 was up to 1.29×10^4 kg m^-3 d^-1, which is more than three times higher than that reported using other methods. Furthermore, the morphologies and porosities of the produced ZIFs could be readily tuned by controlling the synthesis time or type of organic amine. The organic amine played two roles in the synthesis： （1） a protonation agent to deprotonate organic ligands, facilitating the formation of ZIF crystals, and （2） an structure directing agent to direct mesopore/macropore formation. The resulting hierarchical porous ZIF-8 exhibited enhanced uptake capacities and diffusion rates for guest molecules relative to its microporous counterpart. This work provides a new direction for the green and efficient synthesis of various hierarchical porous ZIFs with high STYs for a wide range of applications.展开更多
Palladium(Pd)‐based catalysts are essential to drive high‐performance Suzuki coupling reactions,which are powerful tools for the synthesis of functional organic compounds.Herein,we developed a solution‐rapid‐annea...Palladium(Pd)‐based catalysts are essential to drive high‐performance Suzuki coupling reactions,which are powerful tools for the synthesis of functional organic compounds.Herein,we developed a solution‐rapid‐annealing process to stabilize nitrogen‐mesoporous carbon supported Pd single‐atom/cluster(Pd/NMC)material,which provided a catalyst with superior performance for Suzuki coupling reactions.In comparison with commercial palladium/carbon(Pd/C)catalysts,the Pd/NMC catalyst exhibited significantly boosted activity(100%selectivity and 95%yield)and excellent stability(almost no decay in activity after 10 reuse cycles)for the Suzuki coupling reactions of chlorobenzenes,together with superior yield and excellent selectivity in the fields of the board scope of the reactants.Moreover,our newly developed rapid annealing process of precursor solutions is applied as a generalized method to stabilize metal clusters(e.g.Pd,Pt,Ru),opening new possibilities in the construction of efficient highly dispersed metal atom and sub‐nanometer cluster catalysts with high performance.展开更多
基金supported by the National Natural Science Foundation of China (21576094)SRFDP (20130172110012)the Fundamental Research Funds for the Central Universities (2015ZM046)
文摘Hierarchical porous zeolitic imidazolate frameworks （ZIFs） have potential for adsorption, catalysis and chemical sensing applications. Ultrafast synthesis of ZIFs at room temperature and pressure is particularly desirable for large-scale industrial production. Here, we developed a green and versatile method using organic amines as supramolecular templates （organic amine-template） to rapidly synthesize hierarchical porous ZIFs （ZIF-8, ZIF-61 and ZIF-90） at room temperature and pressure. The synthesis time was reduced dramatically to within 1 min, and the resulting ZIFs had multimodal hierarchical porous structures with mesopores/ macropores interconnected with micropores. Notably, the space-time yield （STY） of hierarchical porous ZIF-8 was up to 1.29×10^4 kg m^-3 d^-1, which is more than three times higher than that reported using other methods. Furthermore, the morphologies and porosities of the produced ZIFs could be readily tuned by controlling the synthesis time or type of organic amine. The organic amine played two roles in the synthesis： （1） a protonation agent to deprotonate organic ligands, facilitating the formation of ZIF crystals, and （2） an structure directing agent to direct mesopore/macropore formation. The resulting hierarchical porous ZIF-8 exhibited enhanced uptake capacities and diffusion rates for guest molecules relative to its microporous counterpart. This work provides a new direction for the green and efficient synthesis of various hierarchical porous ZIFs with high STYs for a wide range of applications.
文摘Palladium(Pd)‐based catalysts are essential to drive high‐performance Suzuki coupling reactions,which are powerful tools for the synthesis of functional organic compounds.Herein,we developed a solution‐rapid‐annealing process to stabilize nitrogen‐mesoporous carbon supported Pd single‐atom/cluster(Pd/NMC)material,which provided a catalyst with superior performance for Suzuki coupling reactions.In comparison with commercial palladium/carbon(Pd/C)catalysts,the Pd/NMC catalyst exhibited significantly boosted activity(100%selectivity and 95%yield)and excellent stability(almost no decay in activity after 10 reuse cycles)for the Suzuki coupling reactions of chlorobenzenes,together with superior yield and excellent selectivity in the fields of the board scope of the reactants.Moreover,our newly developed rapid annealing process of precursor solutions is applied as a generalized method to stabilize metal clusters(e.g.Pd,Pt,Ru),opening new possibilities in the construction of efficient highly dispersed metal atom and sub‐nanometer cluster catalysts with high performance.
