High alkaline stability and long-term durability of imidazole functionalized poly(ether ether ketone) by incorporating graphene oxide/metal-organic framework complex

The poly(ether ether ketone) (PEEK) was prepared as organic matrix. ZIF-8 and GO/ZIF-8 were used as fillers. A series of novel new anion exchange membranes (AEMs) were fabricated with imidazole functionalized PEEK and GO/ZIF-8. The structure of ZIF-8, GO/ZIF-8 and polymers are verified by ¹H NMR, FT-IR and SEM. This series of hybrid membranes showed good thermal stability, mechanical properties and alkaline stability. The ionic conductivities of hybrid membranes are in the range of 39.38 mS cm^?1–43.64 mS cm^?1 at 30 °C, 100% RH and 59.21 mS cm^?1–86.87 mS cm^?1 at 80 °C, 100% RH, respectively. Im-PEEK/GO/ZIF-8-1% which means the mass percent of GO/ZIF-8 compound in Im-PEEK polymers is 1%, showed the higher ionic conductivity of 86.87 mS cm^?1 at 80 °C and tensile strength (38.21 MPa) than that of pure membrane (59.21 mS cm^?1 at 80 °C and 19.47 MPa). After alkaline treatment (in 2 M NaOH solution at 60 °C for 400 h), the ionic conductivity of Im-PEEK/GO/ZIF-8-1% could also maintain 92.01% of the original ionic conductivity. The results show that hybrid membranes possess the ability to coordinate trade-off effect between ionic conductivity and alkaline stability of anion exchange membranes. The excellent performances make this series of hybrid membranes become good candidate for application as AEMs in fuel cells.     

Fe-doped NiCo2S4 catalyst derived from ZIF – 67 towards efficient hydrogen evolution reaction

The development of economical, efficient and stable non-noble metal catalysts plays a key role in electrocatalytic hydrogen evolution. NiCo₂S₄ has been proved to be an efficient non-noble catalyst, to further improve its electrocatalytic performance is a meaningful work. In this paper, the effects of Fe doping on electrochemical performance of NiCo₂S₄ is investigated. The Fe-doped NiCo₂S₄ catalyst is prepared by a facile solvothermal method with metal-organic-framework (MOF, ZIF-67) as template, and it exhibits an improved hydrogen evolution reaction (HER) performance with an overpotential of 181 mV at 10 mA cm^?2, a Tafel slope of 125 mV dec^?1 compared with that of NiCo₂S₄ (252 mV overpotential and 149 mV dec^?1 Tafel slope). The combination of improved conductivity, mesopores architecture retained with the ZIF-67 template, which result the reduced internal resistance, enhanced charge transportation as well as large electrochemical double-layer capacitance. This work provides an effective and synergistic strategy for fabricating NiCo₂S₄-based catalysts toward electrochemical water splitting.     

新型Pt/ZIF-8催化剂的制备及化学固定CO2的研究

文章利用室温扩散法将非离子型表面活性剂PVP修饰的Pt原位负载于ZIF-8上制得新型复合多相催化剂,并探索了其在无溶剂无共催化剂条件下催化CO2与氧化苯乙烯合成苯乙烯碳酸酯的活性。结果表明,Pt明显提高了ZIF-8的催化性能,且所得催化剂的活性随Pt负载量的增加而增强。     

Hydrophilic polymeric membrane supported on silver nanoparticle surface decorated polyester textile: Toward enhancement of water flux and dye removal

A novel mixed matrix nanofiltration membrane was constructed by coating a casting solution containing polyvinylidene fluoride(PVDF), polyethylene glycol(PEG) as hydrophilic agent, zeolitic like framework-67(ZIF-67), ethylenediamine as cross-linking agent on Ag-nanoparticle-decorated polyester textile(PT) support(PT/AgNPs/PVDF-PEG/ZIF-67). PT/Ag-NPs/PVDF-PEG/ZIF-67 morphology, crystalline structure, surface chemical composition and hydrophilicity of PT/Ag-NPs/PVDF-PEG/ZIF-67 were fully characterized by field emission scanning electron microscopy(FE-SEM), X-ray diffraction(XRD), Fourier transform infrared spectroscopy(FT-IR) and water contact angle technique, respectively. PT/Ag-NPs/PVDF-PEG/ZIF-67 was applied in cross module set-up for removal of contaminated water containing rose bengal(RB) dye. The effect of operational parameters such as dye concentration,solution pH and flow rate on performance of PT/Ag-NPs/PVDF-PEG/ZIF-67 were investigated and optimized by central composite design(CCD). Casting solution containing 0.5 wt.% ZIF-67 as optimum value showed the good wettability, high pure water flux(PWF; 35.8 L·m~(-2)·h~(-1)), flux recovery ratio(FRR;90%), dye removal efficiency(96.41%). The selectivity factor of 12.72 and 14.42 was found to be for RB in the presence of amido black and methylene blue as interferent dyes, respectively, which showed a good selective recognition ability for RB dye.     

A microporous carbon derived from metal-organic frameworks for long-life lithium sulfur batteries

A polyhedral microporous carbon derived from metal-organic frameworks (ZIF-8) could present good property for sulfur loading and trapping. A melting-evaporation route was adopted to synthesize two sulfur/microporous carbon (S/MC) composites, of which sulfur content is controllable, and ether-based or ester-based electrolytes were used to evaluate the synthesized composites for the lithium sulfur batteries. According to electrochemical results, the S/MC composite with 65.2 wt% S in the ether-based electrolyte exhibited optimized performance as compared with the composite with 65.2 wt% S in the ester-based electrolyte, as well as the composite with 58.6 wt% S in the two kinds of electrolytes. For the S/MC composite with 65.2 wt% S in ether-based electrolyte, the initial discharge capacity could reach up to 1505.9 mAh g⁻¹ and the reversible capacity could be 833.3 mAh g⁻¹ after 40 cycles at 0.1 C. Furthermore, while being respectively evaluated at 0.5, 1.0, and 2.0 C, the discharge capacities could still maintain at 544, 493 and 354 mAh g⁻¹ after 300, 500, and 800 cycles, demonstrating appreciable cyclic reversibility and rate capability.     

ZIF-8 membrane synthesized via covalent-assisted seeding on polyimide substrate for pervaporation dehydration

In this study, a novel covalent-assisted seeding method is developed to fabricate well-intergrown ZIF-8 membrane on polyimide (PI) substrate with imidazole-2-carboxaldehyde (ICA) as the covalent agent between ZIF-8 layer and PI substrate. Compared to ethylenediamine-crosslinked PI membrane and ZIF-8/PI membrane synthesized without covalent-assisted seeding method, ZIF-8/PI membrane synthesized with ICA covalent-assisted seeding method shows improved pervaporation performance for isopropanol dehydration. Subsequent surface coating with polydimethylsiloxane or polydopamine is applied to mitigate the grain boundary of ZIF-8/PI membrane, which results in a further performance enhancement. The morphologies and physicochemical properties of the resultant membranes are characterized by scanning electron microscope, attenuated total reflectance-Fourier transform infrared, X-ray diffraction, and water contact angle. The effect of operation temperature on the separation performance is also carried out. This work demonstrates the novel covalent-assisted seeding method for the preparation of ZIF-8 membrane with high-performance, which may hold a great potential for various ZIF membranes separation applications.     

Parametric study on the mixed solvent synthesis of ZIF-8 nano- and micro-particles for CO adsorption: A response surface study

The room temperature synthesis of ZIF-8 micro- and nano-particles was investigated using a mixed methanol-water solvent system. ZIF-8 particles of good quality and high crystallinity were obtained. Response surface methodology was used to determine the effect of the synthesis conditions on the ZIF-8 yield, particle size distribution, and mean particle size. The ligand/metal salt molar ratio followed by the amount of sodium formate (the deprotonating agent) and then the amount of water (i.e., the composition of the mixed solvent) respectively had the largest effects on both the ZIF-8 yield and particle size. Results showed that mixing of solvents with different strengths in producing ZIF-8 crystals is a practical method to size-controlled synthesis of ZIF-8 particles. This method is more favorable for industrial-scale ZIF-8 synthesis than using excess amounts of ligands or chemical additives (like sodium formate). In addition, ZIF-8 samples with different mean particle sizes (100, 500, and 1000 nm) were used for CO adsorption and the mid-sized ZIF-8 particles had the highest adsorption capacity.     

TMS320C67xDSP Library在程序开发中的应用

介绍了TIDSP Library的主要特点及其下载和安装方法,分析了TMS320C67xDSP Li-brary的使用性能及其在程序开发中的使用方法,最后给出了一个TIDSP Library的编写实例。