Designed preparation of CoS/Co/MoC nanoparticles incorporated in N and S dual-doped porous carbon nanofibers for high-performance Zn-air batteries

The development of low-cost and highly efficient bifunctional electrocatalysts toward oxygen reduction reaction(ORR) and oxygen evolution reaction(OER) is of critical importance for clean energy devices such as fuel cells and metal-air batteries.Herein,a sophisticated na nostructure composed of CoS,Co and MoC nanoparticles incorporated in N and S dual-doped porous carbon nanofibers(CoS/Co/MoC-N,SPCNFs) as a high-efficiency bifunctional electrocatalyst is designed and synthesized via an efficient multistep strategy.The as-prepared CoS/Co/MoC-N,S-PCNFs exhibit a positive half-wave potential(E_(1/2)) of0.871 V for ORR and a low overpotential of 289 mV at 10 mA/cm~2 for OER,outperforming the non-noble metal-based catalysts reported.Furthermore,the assembled Zn-air battery based on CoS/Co/MoC-N,SPCNFs delivers an excellent power density(169.1 mW/cm~2),a large specific capacity(819.3 mAh/g) and robust durability,demonstrating the great potential of the as-developed bifunctional electrocatalyst in practical applications.This work is expected to inspire the design of advanced bifunctional nonprecious metal-based electrocatalysts for energy storage.     

Vanadium supported on spinel cobalt ferrite nanoparticles as an efficient and magnetically recoverable catalyst for oxidative degradation of methylene blue

Vanadium supported on spinel cobalt ferrite nanoparticles was synthesized and characterized using Fourier transform infrared spectroscopy, X‐ray diffraction, energy‐dispersive X‐ray analysis and transmission electron microscopy. For the first time, the prepared material was used for the catalytic degradation of methylene blue as an organic dye in the presence of hydrogen peroxide as a green oxidant and NaHCO₃ as a co‐reagent at room temperature. The dependency of removal percentage on various parameters such as amount of catalyst, pH, reaction time and temperature and the effect of radical scavenging agents were studied. Finally, recoverability and reusability of the vanadium supported on spinel cobalt ferrite nanoparticles were investigated.     

Synergistic catalysis of isolated Fe~(3+) and Fe_2O_3 on FeO_x/HZSM-5 catalysts for Friedel-Crafts benzylation of benzene

FeO_x/HZSM-5 catalyst with 8 wt.%Fe-loading（8-FeZ） exhibited significantly higher reactivity in the benzylation of benzene with benzyl chloride than FeO_x/HZSM-5 catalyst with 2.5 wt.%Fe-loading（2.5-FeZ） because the synergistic catalysis between isolated Fe³⁺ and superfine Fe₂O₃ occurred on 8-FeZ in the reaction.     

Effects of pretreatment and reduction on the Co/Al2O3 catalyst for CO hydrogenation

The purpose of this study was to investigate the effect of preadsorbed CO at different temperatures, calcination temperatures, the combined influence of reduction temperature and time, and pretreatment using hydrogen or syngas as reduction agents on the F-T synthesis （FTS） activity and selectivity of Co/Al2O3 catalyst. The reactivity of the carbon species at higher preadsorption temperature with H2 in TPSR decreased, whereas the carbon-containing species showed higher reactivity over Co/Al2O3 catalyst with low calcination temperature. This agreed well with the order of catalytic activity for F-T synthesis on this catalyst. The catalytic activity of the catalyst varied with reduction temperature and time remarkably. CODEX optimization gave an optimum reduction temperature of 756 K and reduction time of 6.2 h and estimated C5＋ yield perfectly. The pretreatment of Co/Al2O3 catalyst with different reduction agents （hydrogen or syngas） showed important influences on the catalytic performance. A high CO conversion and C5＋ yield were obtained on the catalyst reduced by hydrogen, whereas methane selectivity on the catalyst reduced by syngas was much higher than that on the catalyst reduced by hydrogen.     

Experimental and molecular-statistical investigation of adsorption of aminoadamantanes on graphitized thermal carbon black

Thermodynamic characteristics of adsorption of some isomeric aminoadamantanes on graphitized thermal carbon black were determined by molecular-statistic calculations and gas-chromatographic measurements. The parameters of the potential function for the pairwise intermolecular interactions between nitrogen in saturated amines and carbon in graphite were calculated. The best agreement between the experimental and calculated Henry constants for 1-aminoadamantane is attained by introducting a correction taking into account the influence of the cage effect on -substituents in the adamantane unit in the parameters of the _N...C(GTCB) atom-atom potential.     

Effect of surface fluorination and conductive additives on the electrochemical behavior of lithium titanate (Li4/3Ti5/3O4) for lithium ion battery

Effect of surface fluorination and conductive additives on the charge/discharge behavior of lithium titanate (Li_4/3Ti_5/3O₄) has been investigated using F₂ gas and vapor grown carbon fiber (VGCF). Surface fluorination of Li_4/3Ti_5/3O₄ was made using F₂ gas (3 × 10⁴ Pa) at 25-150 °C for 2 min. Charge capacities of Li_4/3Ti_5/3O₄ samples fluorinated at 70 °C and 100 °C were larger than those for original sample at high current densities of 300 and 600 mA/g. Optimum fluorination temperatures of Li_4/3Ti_5/3O₄ were 70 °C and 100 °C. Fibrous VGCF with a large surface area (17.7 m²/g) increased the utilization of available capacity of Li_4/3Ti_5/3O₄ probably because it provided the better electrical contact than acetylene black (AB) between Li_4/3Ti_5/3O₄ particles and nickel current collector.     

{[K.18-Crown-6]Br3}n: a unique tribromide-type and columnar nanotube-like structure for the oxidative coupling of thiols and bromination of some aromatic compounds

Reaction of 18-crown-6 with KBr and then with bromine (Br₂) afforded a unique tribromide salt with a nanotube-like structure ({[K.18-crown-6]Br₃}_n). Oxidative coupling of thiols and bromination of some aromatic compounds is the first report on the chemistry of this reagent.     

The stir-frying can reduce hepatorenal toxicity of Fructus Tribuli by inactivating β-glucosidase and inhibiting the conversion of furostanol saponins to spirostanol saponins

The purpose of this study was to illustrate the mechanism of “enzyme inactivation and toxicity reduction” of Fructus Tribuli (FT) after being heating processed. Ultra-high performance liquid chromatography coupled with triple quadrupole tandem mass spectrometry (UHPLC-MS/MS) was used to quantitatively analyze the contents of four steroidal saponins in crude Fructus Tribuli (CFT) and stir-fried Fructus Tribuli (SFT) under different storage times at room temperature. The enzyme activity of β-D-glucosidase in CFT and SFT were determined and calculated by ultraviolet–visible spectrometry (UV-VIS spectrometry). In addition, the enzyme hydrolysates of FOT and tribuluside A were qualitatively analyzed by ultra-high-performance liquid chromatography coupled with quadruple-time-of-flight mass spectrometry (UHPLC-Q-TOF/MS). The hepatorenal toxicity of spirostanol saponins in FT were further confirmed by in vivo and in vitro experiment. This study confirmed that “enzyme inactivation and toxicity reduction” was one of the reasons why the stir-frying can reduce hepatorenal toxicity of FT, and further enriched the exploration on the mechanism of processing toxicity reduction.