Ferrocenyl Ionic Compounds Containing [Fe(CN)6]3– Anions: Synthesis,Characterization, and Catalytic Effects during Combustion

Twenty‐eight novel ferrocenyl ionic compounds, composed of mononuclear 1‐ferrocenylmethylalkyldimethylammoniums, 1‐ferrocenylmethyl‐3‐alkylimidazoliums, or their dinuclear analogs and [Fe(CN)₆]^3– anion, were designed and synthesized to tackle significant volatility and migration tendency of ferrocene‐based burning rate catalysts (BRCs) used currently in the composite solid propellants. The new compounds were characterized by UV/Vis, FT‐IR, and elementary analysis. The crystal structures of compounds 2· 5H₂O and 3· CH₂Cl₂ · 4H₂O verified the successful preparation of the desired ionic compounds. The TG tests at 70 °C for 24 h revealed that the new compounds exhibit lower volatility than catocene. The cyclic‐voltammetry results suggested that new compounds are quasi‐reversible or irreversible redox systems. TheTG/DSC analyses exhibited that the compounds are of highly thermal stability. Their catalytic effects on the thermal degradation of ammonium perchlorate (AP), 1,3,5‐trinitro‐1,3,5‐triazacyclohexane (RDX), and 1,3,5,7‐tetranitro‐1,3,5,7‐tetrazacyclooctane (HMX) were investigated. The results showed that most of the compounds exert great effects on the thermal degradation of AP and RDX during combustion. 11 and 2 are comparable to catocene in the thermal decomposition of AP and RDX, respectively, and can therefore be used as alternatives of catocene in a composite solid propellant. Some new compounds are unexpectedly active in promoting the thermal disintegration of HMX.     

Porous ZnO/Co3O4/N‐doped carbon nanocages synthesized via pyrolysis of complex metal–organic framework (MOF) hybrids as an advanced lithium‐ion battery anode

Metal oxides have a large storage capacity when employed as anode materials for lithium‐ion batteries (LIBs). However, they often suffer from poor capacity retention due to their low electrical conductivity and huge volume variation during the charge–discharge process. To overcome these limitations, fabrication of metal oxides/carbon hybrids with hollow structures can be expected to further improve their electrochemical properties. Herein, ZnO‐Co₃O₄ nanocomposites embedded in N‐doped carbon (ZnO‐Co₃O₄@N‐C) nanocages with hollow dodecahedral shapes have been prepared successfully by the simple carbonizing and oxidizing of metal–organic frameworks (MOFs). Benefiting from the advantages of the structural features, i.e. the conductive N‐doped carbon coating, the porous structure of the nanocages and the synergistic effects of different components, the as‐prepared ZnO‐Co₃O₄@N‐C not only avoids particle aggregation and nanostructure cracking but also facilitates the transport of ions and electrons. As a result, the resultant ZnO‐Co₃O₄@N‐C shows a discharge capacity of 2373 mAh g^?1 at the first cycle and exhibits a retention capacity of 1305 mAh g^?1 even after 300 cycles at 0.1 A g^?1. In addition, a reversible capacity of 948 mAh g^?1 is obtained at a current density of 2 A g^?1, which delivers an excellent high‐rate cycle ability.     

热活化延迟荧光聚合物及其电致发光器件

热活化延迟荧光(TADF)聚合物,不仅具有小分子TADF材料高的激子利用效率特性,而且还具备分子多样性好、可溶液加工、低成本、以及易实现大面积柔性器件等诸多优势,在近几年受到广泛的关注并展现了良好的应用前景。本文从TADF聚合物分子设计原理、器件结构及发光机理出发,依据TADF聚合物的构筑方法不同,概括了其结构设计策略,详述了各种类型TADF聚合物的分子结构和光电性能及其在有机电致发光器件领域应用的研究进展,最后探讨了TADF聚合物存在的问题,并展望了其发展前景。     

CuFeS2 as an anode material with an enhanced electrochemical performance for lithium-ion batteries fabricated from natural ore chalcopyrite

Journal of Solid State Electrochemistry - Considering serious pollution from the traditional chemical synthesis process, the resource-rich, clean electrode materials are greatly desired....     

Rhodium(III)-catalyzed direct C-7 sulfonamidation and amination of indolines with arylsulfonamides and trifluoroacetamide

A rhodium-catalyzed direct C–H sulfonamidation and amidation of C-7 position of indolines by simple and commercially available arylsulfonamides and trifluoroacetamide has been developed, affording a series of N-arylsulfonamides and N-aryltrifluoroacetamides in moderate to excellent yields, respectively. Notably, this catalytic system is highly convenient on mmol scale.     

Facile synthesis of mesoporous WO3@graphene aerogel nanocomposites for low-temperature acetone sensing

Nanocomposites constructed by combining mesoporous metal oxides and graphene have received tremendous attention in wide fields of catalysis,energy storage and conversion,gas sensing and so on.Herein,we present a facile interface-induced co-assembly process to synthesize the mesoporous W03@graphene aerogel nanocomposites(denoted as mW03@GA),in which graphene aerogel(GA) was used as a macroporous substrate,mesoporous W03 was uniformly coated on both sides of graphene sheets through a solvent evaporation-induced self-assembly(EISA) strategy using diblock copolymer poly(ethylene oxide)-b-polystyrene(PEO-b-PS) as a template.The resultant mW03@GA nanocomposites possess well-interconnected macroporous graphene networks covered by mesoporous W03 layer with a uniform pore size of 19 nm,high surface area of 167 m~2/g and large pore volume of 0.26 cm~3/g.The gas sensing performance of mW03@GA nanocomposites toward acetone and other gases was studied,showing a high selectivity and great response to acetone at low temperature of 150℃,which could be developed as a promising candidate as novel sensors for VOCs detection.     

Novel CaCO3/g-C3N4 composites with enhanced charge separation and photocatalytic activity

A novel CaCO₃/graphitic carbon nitride (g-C₃N₄) photocatalyst was synthesized for the first time via a facile calcination method using CaCO₃ and melamine as precursors. The as-prepared samples were characterized using various techniques, such as scanning and transmission electron microscopy, X-ray diffraction, Brunauer-Emmett-Teller analysis, as well as Fourier-transform infrared, X-ray photoelectron, photoluminescence, and UV–vis diffuse reflectance spectroscopy. The results of the experiments confirm the successful coupling of CaCO₃ to g-C₃N₄. The photocatalytic activity of the synthesized CaCO₃/g-C₃N₄ composites was evaluated by assessing their performance in the photocatalytic degradation of crystal violet (CV) in water under visible light irradiation. The analysis shows that CaCO₃/g-C₃N₄ exhibits higher photocatalytic activity towards CV degradation (76.0%) than pristine g-C₃N₄ (21.6%) and CaCO₃ (23.2%). Radical trapping and electron spin resonance experiments show that hydroxyl radicals (OH) and holes (h⁺) are the key reactive species in the photocatalytic process. The enhanced photocatalytic activity of the composite is mainly attributed to the efficient separation rate of electron-hole pairs achieved through the incorporation of CaCO₃.     

Efficient Fe‐Co‐N‐C Electrocatalyst Towards Oxygen Reduction Derived from a Cationic CoII‐based Metal–Organic Framework Modified by Anion‐Exchange with Potassium Ferricyanide

Fe‐Co‐N‐C electrocatalysts have proven superior to their counterparts (e.g. Fe‐N‐C or Co‐N‐C) for the oxygen reduction reaction (ORR). Herein, we report on a unique strategy to prepare Fe‐Co‐N‐C?x (x refers to the pyrolysis temperature) electrocatalysts which involves anion‐exchange of [Fe(CN)₆]^3? into a cationic Co^II‐based metal‐organic framework precursor prior to heat treatment. Fe‐Co‐N‐C‐900 exhibits an optimal ORR catalytic performance in an alkaline electrolyte with an onset potential (E_onset: 0.97 V) and half‐wave potential (E_1/2: 0.86 V) comparable to that of commercial Pt/C (E_onset=1.02 V; E_1/2=0.88 V), which outperforms the corresponding Co‐N‐C‐900 sample (E_onset=0.92 V; E_1/2=0.84 V) derived from the same MOF precursor without anion‐exchange modification. This is the first example of Fe‐Co‐N‐C electrocatalysts fabricated from a cationic Co^II‐based MOF precursor that dopes the Fe element via anion‐exchange, and our current work provides a new entrance towards MOF‐derived transition‐metal (e.g. Fe or Co) and nitrogen‐codoped carbon electrocatalysts with excellent ORR activity.