1D compound [Zn(Im)(HIm) 2 (OAc)] was used as a single precursor of metal and imidazole to prepare several 3-dimensional (3D) Zn(Im) 2 frameworks by solution-mediated transformation. Specifically, three known topologies, zni, coi and crb (BCT) were obtained using a solution-mediated transformation with CH 3 OH, DMF and DMA as solvent, respectively. Structural studies by 13 C MAS NMR spectroscopy and TG imply that in the transformation process from 1D compound to coi-[Zn(Im) 2 ]•(DMF) x and crb-[Zn(Im) 2 ]•(DMA) x (ZIF-1), DMF and DMA solvent molecules acted as structure-directing agent and, therefore, were occluded inside the framework, respectively. In contrast, in the formation of zni-[Zn(Im) 2 ], no solvent molecules were present in the frameworks; therefore the transformation from 1D compound to zni was induced by temperature. Thus, solution-mediated transformation of a single precursor (1D compound) approach was established for the synthesis of ZIFs.
Jingqiu Li,Yuming Xie,Mengjue Cao,Yi Feng,Jianfeng Yao
The metal ion etching induced transformation of zeolitic imidazolate frameworks (ZIFs) to layered double hydroxides (LDHs) is closely related to the etching conditions. Here, by tuning the Ni 2+ etching conditions (e.g., initial Ni 2+ concentration and etching time), Co-ZIF-L templated CoNi-LDH with diverse morphologies and tailorable compositions are obtained and their resultant electrochemical properties are optimized. Mechanism study reveals that the etching conditions significantly affect the disassembling rate of Co-ZIF-L as well as the formation rate of CoNi-LDH, leading to the morphological and compositional variance of etched samples, which further results in their distinct electrochemical activities. The resultant asymmetric supercapacitor assembled with Co-ZIF-L derived CoNi-LDH and activated carbon can achieve a maximum energy density of 77.3 Wh/kg at a power density of 700 W/kg with the capacity retention of 85.7 % after 2000 cycles, superior or comparable to other advanced CoNi-LDH based supercapacitors .
危险品化学品经营许可证（带存储）