Carbon super-heterostructures with high nitrogen contents from the covalent hybrid precursors of covalent triazine frameworks(CTFs)and zeolitic imidazolic frameworks(ZIFs)are scarcely explored because of CTF's ord...Carbon super-heterostructures with high nitrogen contents from the covalent hybrid precursors of covalent triazine frameworks(CTFs)and zeolitic imidazolic frameworks(ZIFs)are scarcely explored because of CTF's ordered structure and toxic superacid that dissolves or destabilizes the metal nodes.To solve this problem,herein,we report a straightforward two-step pathway for the covalent hybridization of disordered CTF(d–CTF)–ZIF composites via preincorporation of an imidazole(IM)linker into ordered CTFs,followed by the imidazole-site-specific covalent growth of ZIFs.Direct carbonization of these synthesized d–CTF−IM−ZIF hybrids results in unique hollow carbon super-heterostructures with ultrahigh nitrogen content(>18.6%),high specific surface area(1663m^(2)g^(−1)),and beneficial trace metal(Co/Zn NPs)contents for promoting the redox pseudocapacitance.As proof of concept,the obtained carbon super-heterostructure(Co–Zn–NC_(SNH)–800)is used as a positive electrode in an asymmetric supercapacitor,demonstrating a remarkable energy density of 61Wh kg^(−1)and extraordinary cyclic stability of 97%retention after 30,000 cycles at the cell level.Our presynthetic modifications of CTF and their covalent hybridization with ZIF crystals pave the way toward new design strategies for synthesizing functional porous carbon materials for promising energy applications.展开更多
A novel series of UiO-66 structures with linker-induced defects was synthesized and fully characterized.By using a linker functionalized with a free,dangling alkylamine that replaces the ordinary carboxylate coordinat...A novel series of UiO-66 structures with linker-induced defects was synthesized and fully characterized.By using a linker functionalized with a free,dangling alkylamine that replaces the ordinary carboxylate coordinating group,up to 40%of the linkers incorporated within the UiO-66 framework were defect sites.The resulting UiO-66 with linker-induced defects was then demonstrated to be a highly active heterogeneous catalyst.When applied to three-component,solvent-free cycloadditions of epoxides with aromatic amines and CO_(2)at ambient pressure,a diverse range of bioactive oxazolidinone compounds were isolated in significantly high yields(>90%)with quantitative conversions and regioselectivity.Finally,the catalyst was proven recyclable over 5 consecutive reactions without loss of performance.展开更多
基金Ministry of Trade,Industry&Energy of Korea,Grant/Award Number:RS‐2022‐00155717National Research Foundation of Korea,Grant/Award Numbers:2020H1D3A1A04081472,2022M3J1A1054323。
文摘Carbon super-heterostructures with high nitrogen contents from the covalent hybrid precursors of covalent triazine frameworks(CTFs)and zeolitic imidazolic frameworks(ZIFs)are scarcely explored because of CTF's ordered structure and toxic superacid that dissolves or destabilizes the metal nodes.To solve this problem,herein,we report a straightforward two-step pathway for the covalent hybridization of disordered CTF(d–CTF)–ZIF composites via preincorporation of an imidazole(IM)linker into ordered CTFs,followed by the imidazole-site-specific covalent growth of ZIFs.Direct carbonization of these synthesized d–CTF−IM−ZIF hybrids results in unique hollow carbon super-heterostructures with ultrahigh nitrogen content(>18.6%),high specific surface area(1663m^(2)g^(−1)),and beneficial trace metal(Co/Zn NPs)contents for promoting the redox pseudocapacitance.As proof of concept,the obtained carbon super-heterostructure(Co–Zn–NC_(SNH)–800)is used as a positive electrode in an asymmetric supercapacitor,demonstrating a remarkable energy density of 61Wh kg^(−1)and extraordinary cyclic stability of 97%retention after 30,000 cycles at the cell level.Our presynthetic modifications of CTF and their covalent hybridization with ZIF crystals pave the way toward new design strategies for synthesizing functional porous carbon materials for promising energy applications.
基金Saudi Aramco for financial support through the CO_(2)Capture and Utilization Chair Program(no.ORCP2390)。
文摘A novel series of UiO-66 structures with linker-induced defects was synthesized and fully characterized.By using a linker functionalized with a free,dangling alkylamine that replaces the ordinary carboxylate coordinating group,up to 40%of the linkers incorporated within the UiO-66 framework were defect sites.The resulting UiO-66 with linker-induced defects was then demonstrated to be a highly active heterogeneous catalyst.When applied to three-component,solvent-free cycloadditions of epoxides with aromatic amines and CO_(2)at ambient pressure,a diverse range of bioactive oxazolidinone compounds were isolated in significantly high yields(>90%)with quantitative conversions and regioselectivity.Finally,the catalyst was proven recyclable over 5 consecutive reactions without loss of performance.
