Characterization and reactivity of γ-Al_2O_3 supported Pd–Ni bimetallic nanocatalysts for selective hydrogenation of cyclopentadiene

Several g-Al2O3 supported Pd–Ni bimetallic nanocatalysts(Pd–Ni(x:y)/Al2O3; where x and y represent the mass ratio of Pd and Ni, respectively) were prepared by the impregnation method and used for selective hydrogenation of cyclopentadiene to cyclopentene. The Pd–Ni/Al2O3 samples were confirmed to generate Pd–Ni bimetallic nanoparticles by X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS) and transmission electron microscopy(TEM). The catalytic activity was assessed in view of the effects of different mass ratios of Pd and Ni, temperature, pressure, etc. Among all the samples, the Pd–Ni(1:1)/Al2O3(PN-1:1) catalyst showed extremely high catalytic ability. The conversion of cyclopentadiene and selectivity for cyclopentene can be simultaneously more than 90%.     

Development of a magnetic solid‐phase extraction coupled with high‐performance liquid chromatography method for the analysis of polyaromatic hydrocarbons

A novel magnetic solid phase extraction coupled with high‐performance liquid chromatography method was established to analyze polyaromatic hydrocarbons in environmental water samples. The extraction conditions, including the amount of extraction agent, extraction time, pH and the surface structure of the magnetic extraction agent, were optimized. The results showed that the amount of extraction agent and extraction time significantly influenced the extraction performance. The increase in the specific surface area, the enlargement of pore size, and the reduction of particle size could enhance the extraction performance of the magnetic microsphere. The optimized magnetic extraction agent possessed a high surface area of 1311 m²/g, a large pore size of 6–9 nm, and a small particle size of 6–9 μm. The limit of detection for phenanthrene and benzo[g,h,i]perylene in the developed analysis method was 3.2 and 10.5 ng/L, respectively. When applied to river water samples, the spiked recovery of phenanthrene and benzo[g,h,i]perylene ranged from 89.5–98.6% and 82.9–89.1%, respectively. Phenanthrene was detected over a concentration range of 89–117 ng/L in three water samples withdrawn from the midstream of the Huai River, and benzo[g,h,i]perylene was below the detection limit.     

智能性水凝胶

“智能”材料具有传感、处理和执行功能，水凝胶作为智能材料其应用前景良好。本文综述了智能水凝胶的近期研究发展，以Ｆｌｏｒｙ的溶胀理论着重探讨了刺激响应性，并介绍了化学机械现象及凝胶相转变。     

Pattern-dependent tunable adhesion of superhydrophobic MnO2 nanostructured film

Tuning the adhesive force on a superhydrophobic MnO(2) nanostructured film was achieved by fabricating different patterns including meshlike, ball cactus-like, and tilted nanorod structures. The marvelous modulation range of the adhesive forces from 130 to nearly 0 μN endows these superhydrophobic surfaces with extraordinarily different dynamic properties of water droplets. This pattern-dependent adhesive property is attributed to the kinetic barrier difference resulting from the different continuity of the three-interface contact line. This finding will provide the general strategies for the adhesion adjustment on superhydrophobic surfaces.     

Phase and Interface Engineering of Platinum–Nickel Nanowires for Efficient Electrochemical Hydrogen Evolution

The design of high‐performance electrocatalysts for the alkaline hydrogen evolution reaction (HER) is highly desirable for the development of alkaline water electrolysis. Phase‐ and interface‐engineered platinum–nickel nanowires (Pt‐Ni NWs) are highly efficient electrocatalysts for alkaline HER. The phase and interface engineering is achieved by simply annealing the pristine Pt‐Ni NWs under a controlled atmosphere. Impressively, the newly generated nanomaterials exhibit superior activity for the alkaline HER, outperforming the pristine Pt‐Ni NWs and commercial Pt/C, and also represent the best alkaline HER catalysts to date. The enhanced HER activities are attributed to the superior phase and interface structures in the engineered Pt‐Ni NWs.     

Ordered Solid‐State Microstructures of Conjugated Polymers Arising from Solution‐State Aggregation

Controlling the solution‐state aggregation of conjugated polymers for producing specific microstructures remains challenging. Herein, a practical approach is developed to finely tune the solid‐state microstructures through temperature‐controlled solution‐state aggregation and polymer crystallization. High temperature generates significant conformation fluctuation of conjugated backbones in solution, which facilitates the polymer crystallization from solvated aggregates to orderly packed structures. The polymer films deposited at high temperatures exhibit less structural disorders and higher electron mobilities (up to two orders of magnitude) in field‐effect transistors, compared to those deposited at low temperatures. This work provides an effective strategy to tune the solution‐state aggregation to reveal the relationship between solution‐state aggregation and solid‐state microstructures of conjugated polymers.     

Photocatalytic Activity of Fe and Ce Co‐doped Mesoporous TiO2 Catalyst under UV and Visible Light

The catalysts of un‐doped, single‐doped and co‐doped mesoporous titanium dioxide (MTiO₂) were prepared by a template method with tetrabutyltitanate (Ti(OC₄H₉)₄) as a Ti source material and Pluronic P123 as a template. The photo‐absorbance of the obtained catalysts was measured by UV‐vis absorption spectroscopy, and the photocatalytic activities of the prepared samples under UV and visible light were estimated by measuring the degradation rate of methyl orange (MO) (50 mg/L) in an aqueous solution. It was shown that the co‐doped MTiO₂ could be activated by visible light and could thus be used as an effective catalyst in photo‐oxidation reactions. The effect of Fe and Ce co‐dopants on the material properties was investigated by X‐ray diffraction (XRD), scanning electron microscopy (SEM) and N₂ adsorption‐desorption isotherm measurement. The characterizations indicated that the photocatalysts possessed a homogeneous pore diameter of ca. 10 nm with high surface area of ca. 150 m²/g. The photocatalytic activity of MTiO₂ co‐doped with Fe and Ce was markedly improved due to the synergistic actions of the two dopants.     

Strong Convergence of an Iterative Method with Perturbed Mappings for Nonexpansive and Accretive Operators

A new iterative method for finding a zero of m-accretive operators is proposed. This method, involving a so-called perturbed mapping, provides a way to construct sunny nonexpansive retractions. Several strong convergence theorems for this method are established in a Banach space that is either uniformly smooth or reflexive with a weakly continuous duality map.