负载硫化钴纳米颗粒的N、S共掺杂石墨烯氧还原电催化剂的制备及性能

采用D-氨基葡萄糖作为Co分散剂和碳源,硫脲作为氮源和硫源,以NaCl为模板制备负载硫化钴纳米颗粒的N、S共掺杂三维石墨烯氧还原电催化剂(CoS/N/S/rGO)。CoS/N/S/rGO具有良好的氧还原反应(ORR)活性,起始电位和半波电位分别为960和815 mV,性能与商业Pt/C相当。此外,CoS/N/S/rGO表现出明显的4电子转移特性和超低的过氧化氢产率。与基于Pt/C的锌-空气电池相比,基于CoS/N/S/rGO的锌-空气电池在6 mol·L~(-1) KOH和0.2 mol~(-1) Zn(CH_3COO)_2碱性电解质中显示出更高的恒电流放电性能以及更好的稳定性。     

Differential Cross Sections of F+HD→DF+H Reaction at Collision Energies from 3.03 meV to 17.97 meV

The prototypical reaction of F+HD→DF+H was investigated at collision energies from 3.03 meV to 17.97 meV using a crossed molecular beam apparatus with multichannel Rydberg tagging time-of-flight detection. Significant contributions from both the Born-Oppenheimer (BO) forbidden reaction F^*(²P_1/2)+HD→DF+H and the BO-allowed reaction F(²P_3/2)+HD→DF+H were observed. In the backward scattering direction, the contribution from the BO-forbidden reaction F^*(²P_1/2)+HD was found to be considerably greater than the BO-allowed reaction F(²P_3/2)+HD, indicating the non-adiabatic effects play an important role in the dynamics of the title reaction at low collision energies. Collision-energy dependence of differential cross sections (DCSs) in the backward scattering direction was found to be monotonously decreased as the collision energy decreases, which does not support the existence of resonance states in this energy range. DCSs of both BO-allowed and BO-forbidden reactions were measured at seven collision energies from 3.03 meV to 17.97 meV. It is quite unexpected that the angular distribution gradually shifts from backward to sideway as the collision energy decreases from 17.97 meV to 3.03 meV, suggesting some unknown mechanisms may exist at low collision energies.     

High electrochemiluminescence of a new water-soluble iridium(III) complex for determination of antibiotics

A new water-soluble iridium(III) diimine complex with appended sugar was synthesized and characterized. The electrochemiluminescent behavior of the new complex in aqueous buffer was first studied and the ECL signal was found to be much higher than that of [Ru(bpy)(3)](2+) at a Pt working electrode. Tri-n-propylamine (TPA) and antibiotics were determined by the ECL of the iridium(III) complex in aqueous buffer at the Pt electrode and the method was found to show good sensitivity and reproducibility. The new iridium(III) complex was found to display good solubility in aqueous solution and a strong ECL signal at the Pt electrode, which might open up the possibility of its application in analysis.     

Covalently bonded polysaccharide-modified stationary phase for per aqueous liquid chromatography and hydrophilic interaction chromatography

The mixed sulfated/methacryloyl polysaccharide derivative was prepared and successfully immobilized onto the surface of porous silica particles by polymerization. Polysaccharide derivative was calculated as 10.33% in the stationary phase prepared. The new stationary phase (PMSP) showed both hydrophilic interaction (HILIC) and per aqueous liquid chromatography (PALC) characteristics. The effects of column temperature, the water content, pH and ion strength of mobile phase on the retention time of test compounds in highly aqueous eluents were investigated to evaluate the PALC features of PMSP. The column efficiency is about 31,000 plates/m for benzoic acid in water/ACN (97/3, v/v) mobile phase at a flow rate of 1.0 mL/min. Compared with C18 column, the PMSP had shorter retention time for weak polar and non-polar compounds, but also showed stronger retention for strong polar compounds. It indicated that PALC was a suitable mode of chromatography as replacement of HILIC and complementarity of reversed-phase liquid chromatography (RPLC).     

Iron-facilitated direct oxidative C-H transformation of allyl arenes to alkenyl aldehydes

A direct oxidative approach to alkenyl aldehydes from allyl arenes via allyl sp³ C-H functionalization was disclosed. An inexpensive iron catalyst was employed to facilitate this transformation. The mechanistic studies indicate that the cleavage of the allyl sp³ C-H bond is involved in the rate-determining step.     

邻氨基酚-过氧化氢-辣根过氧化物酶伏安酶联免疫分析法测定人血清甲胎蛋白

提出了邻氨基酚（ＯＡＰ）－Ｈ２Ｏ２－辣根过氧化物酶（ＨＲＰ）伏安酶联免疫分析法测定人血清甲胎蛋白（α－ＦＰ）的新方法．该方法是将ＨＲＰ催化Ｈ２Ｏ２氧化邻氨基酸的酶催化反应与邻氨基酚的氧化产物在滴汞电极上的还原反应相偶合，在ＢＲ缓冲溶液中，在－０．４３ Ｖ（ｖｓ．ＳＣＥ）左右产生灵敏的极谱波．根据测定标记在甲胎蛋白抗体上的ＨＲＰ的量，求得发生免疫反应的 α－ＦＰ的含量。该方法对甲胎蛋白测定的线性范围为 １． ２５～４００ ｍｇ／Ｌ。用所建立的方法对病人血清样品进行了测定，并与酶联免疫吸附测定光度法（ＥＬＩＳＡ）进行对照，二者相关性很好。     

Surface structure and energetics of hydrogen adsorption on the Fe(111) surface

Spin-polarized density functional theory calculations have been performed to characterize the hydrogen adsorption and diffusion on the Fe(111) surface at 2/3-, 1-, and 2-monolayer (ML) coverages. It is found that the most favored adsorption site for atomic hydrogen (H) is the top-shallow bridge site (tsb), followed by the quasi 4-fold site (qff) with the energy difference of about 0.1 eV, while the top site (t) is not competitive. Furthermore, the adsorbed atomic hydrogen (H) has a high mobility, as indicated by the small diffusion barriers. The local density of state (LDOS) analysis reveals that the Fe-H (tsb or qff) bond involves mainly the Fe 4s and 4p and H 1s orbitals with less contribution of the Fe 3d orbital, while the Fe 4s, 4p, and 3d orbitals all participate in the Fe-H (top) bond. In addition, the coverage effects on the adsorption configurations and adsorption energies are addressed.     

Chemisorption of CO2 on nickel surfaces

CO2 chemisorption on the Ni(111), Ni(100), and Ni(110) surfaces was investigated at the level of density functional theory. It was found that the ability of CO2 chemisorption is in the order of Ni(110) > Ni(100) > Ni(111). CO2 has exothermic chemisorption on Ni(110) and endothermic chemisorption on Ni(111), while it is thermally neutral on Ni(100). It is also found that there is no significant lateral interaction between the adsorbed CO2 at 1/4 monolayer (ML) coverage, while there is stronger repulsive interaction at 1/2 ML. On all surfaces, the chemisorbed CO2 is partially negatively charged, indicating the enhanced electron transfer, and the stronger the electron transfer, the stronger the C=O bond elongation. The bonding nature of the adsorbed CO2 on nickel surfaces has been analyzed. The thermodynamics of CO2 dissociative chemisorption, compared with CO and O adsorption, has been discussed, and the thermodynamic preference is in the sequence Ni(100) > Ni(111) > Ni(110).     

A Simple and Efficient Copper(Ⅱ) Complex as a Catalyst for N-Arylation of Imidazoles

Four inexpensive and air‐/moisture‐stable pyrrolecarbaldiminato‐Cu complexes 1 – 4 were synthesized and evaluated to be a novel class of catalysts for the N‐arylation of imidazoles with aryl halides. A variety of aryl iodides, bromides and activated aryl chlorides underwent the coupling with imidazoles, promoted by the catalyst 4 , in moderate to good yields without the protection by an inert gas.