Multiarylpolycarboxylate-Mediated Hybrid Cobalt Phosphate Frameworks with Supramolecular Zeolitic Topology and Unusual I2O2 Connectivity

Coordination Polymer Derived Porous Carbon Activated in Situ by the ZnCl2 Dot: Capacitances Greatly Enhanced by Redox-Activity Additives in Electrolytes

Herein, a 1D zinc coordination polymer [Zn(bibp)Cl₂]_∞ (CP-2-ZX) was assembled from the reaction of 4,4'-bis(imidazol-1-yl)-biphenyl (bibp) with ZnCl₂. Through a calcination-thermolysis strategy, sponge-like highly porous carbon AC-Zn-CP was prepared by employing the coralloid sample of CP-2-ZX as the precursor. For comparisons, a series of activated carbon (AC-n) was obtained by the similar heating process on the mixture of bibp with ZnCl₂ at different mass ratios. The results illustrate that the atomically dispersed ZnCl₂ dot in the 1D chain of CP-2-ZX has an in situ activation effect on the generation of AC-Zn-CP, which can greatly promote the porosity and achieve high-efficiency utilization of ZnCl₂. Therefore, the atomically dispersed activating agent provides a new method for environmentally friendly production of porous carbon materials. Significantly, the AC-Zn-CP electrode displays specific capacitance of 215 F g^-1 in 3 M KOH solution, which will be largely promoted to 1419 F g^-1 in the redox active electrolyte of K₃[Fe(CN)₆]/KOH. AC-Zn-CP also shows remarkable cycling stability (the capacity retention is 89.0% after 5000 cycles). Moreover, the fabricated symmetric supercapacitor owns a high energy density of 34.8 Wh kg^-1 at 785.5 W kg^-1. So, the AC-Zn-CP∩K₃[Fe(CN)₆] system has wide application prospects in supercapacitors.

Benzoate Acid-Dependent Lattice Dimension of Co-MOFs and MOF-Derived CoS2@CNTs with Tunable Pore Diameters for Supercapacitors

Herein three novel cobalt metal-organic frameworks (Co-MOFs) with similar ingredients, [Co(bib)(o-bdc)]_∞ (1), [Co₂(bib)₂(m-bdc)₂]_∞ (2), and {[Co(bib)(p-bdc)(H₂O)](H₂O)_0.5}_∞ (3), have been synthesized from the reaction of cobalt nitrate with 1,4-bis(imidazol-1-yl)benzene (bib) and structure-related aromatic acids (1,2-benzenedicarboxylic acid = o-bdc, 1,3-benzenedicarboxylic acid = m-bdc, and 1,4-benzenedicarboxylic acid = p-bdc) by the solvothermal method. It is aimed to perform systematic research on the relationship among the conformation of benzoate acid, lattice dimension of Co-MOF, and pore diameter of MOF-derived carbon composite. Through the precursor strategy, Co-MOFs 1-3 have been utilized to synthesize porous cobalt@carbon nanotube composites (Co@CNTs). After the in situ gas-sulfurization, secondary composites CoS₂@CNTs were successfully obtained, which kept similar morphologies of corresponding Co@CNTs without destroying previous highly dispersed structures. Co-MOFs and two series of composites (Co@CNTs and CoS₂@CNTs) have been well characterized. Topology and Brunauer-Emmett-Teller analyses elucidate that the bdc^2- ion could control the pore diameters of MOF-derived carbon composites by adjusting the lattice dimension of Co-MOFs. The systematic studies on electrochemical properties demonstrate that (p)-CoS₂@CNT possesses hierarchical morphology, moderate specific surface area, proper pore diameter distribution, and high graphitization, which lead to remarkable specific capacitances (839 F g^-1 at 5 mV s^-1 and 825 F g^-1 at 0.5 A g^-1) in 2 M potassium hydroxide solution. In addition, the (p)-CoS₂@CNT electrode exhibits good electrochemical stability and still retains 82.9% of initial specific capacitance at the current density of 1 A g^-1 after 5000 cycles.

An unprecedented organic–inorganic hybrid material with an I3O3 framework based on cadmium hydroxide and in situ generated 1H-tetrazolate-5-acetic acid

A novel I³O³ hybrid framework was generated, based on a rare ths inorganic subnet of cadmium hydroxide and 3-D organic network linked by tza²⁻ ligands and Cd(ii) centers.

Solvent-free synthesis of new metal phosphate–oxalates: influence of different metal ions on the framework structures

The influence of different metal ions on the framework structures was investigated under solvent-free conditions, which gave rise to six new metal phosphate–oxalates with mmt, ins, fsd, and hcb topologies, respectively.

Dielectric response and anhydrous proton conductivity in a chiral framework containing a non-polar molecular rotor

A chiral 3D framework containing a nonpolar rotor shows two dielectric anomalies and can serve as a proton conductor under high-temperature and anhydrous conditions.