One step NaBH4 reduction of Pt-Ru-Ni catalysts on different types of carbon supports for direct ethanol fuel cells: Synthesis and characterization

The ternary catalyst Pt₇₅Ru₅Ni₂₀ was conducted on various types of carbon supports including functionalized Vulcan XC-72R (f-CB), functionalized multi-walled carbon nanotubes (f-MWCNT), and mesoporous carbon (PC-Zn-succinic) by sodium borohydride chemical reduction method to improve the ethanol electrooxidation reaction (EOR) for direct ethanol fuel cell (DEFC). It was found that the particle size of the metals on f-MWCNT was 5.20 nm with good particle dispersion. The alloy formation of ternary catalyst was confirmed by XRD and more clearly described by SEM element mapping, which was relevant to the efficiency of the catalysts. Moreover, the mechanism of ethanol electrooxidation reaction based on the surface reaction was more understanding. The activity and stability for ethanol electrooxidation reaction (EOR) were investigated using cyclic voltammetry and chronoamperometry, respectively. The highest activity and stability for EOR were observed from Pt₇₅Ru₅Ni₂₀/f-MWCNT due to a good metal-carbon interaction. Ru and Ni presented in Pt-Ru-Ni alloy improved the activity and stability of ternary catalysts for EOR. Moreover, the reduction of Pt content in ternary catalyst led to the catalyst cost deduction in DEFC.     

Micro-/Mesoporous conjugated polymer based on star-shaped triazine-functional triphenylamine framework as the performance-improved cathode of Li-organic battery

A novel organic conjugated polymer based on star-shaped triazine-functional triphenylamine framework poly[1,3,5-tris(4-diphenylamino-phenyl)triazine] (PTDAPTz) is designed and synthesized successfully by FeCl₃-catalysted chemical oxidative polymerization. The polymer PTDAPTz powder exhibits a compactly packed pleated skirt shape-like morphology with a high surface area (~930 m² g⁻¹) and a bimodal pore size distribution ranging from micropores (~0.55 nm) to small diameter mesopores (~2–6 nm). As explored as the cathode material, the obtained PTDAPTz presents the double charge–discharge process characteristics of both the free radical redox of triphenylamine unit and the bipolar redox of triazine unit in the polymer and a well-defined multistage charge/discharge voltage plateau (~3.8 V for p-doped and ~2.0 V for n-doped) during the charge–discharge process. Also, the PTDAPTz demonstrates an improved capacity (stabilized at 123 mA h g⁻¹ until 50th cycle) and the enhanced rate performance compared to polytriphenylamine (PTPAn). Specially, the discharge curve for the part of triphenylamine unit presents an obviously improved discharge plateau (~3.8 V for PTDAPTz compared to ~3.6 V for PTPAn) due to the electron-withdrawing effect of the triazine unit to triphenylamine. The elaborate structural design and created micro-/mesoporous morphology with the double charge–discharge process make PTDAPTz a potential candidate as the performance-improved cathode of Li-organic battery. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 2574–2583     

Surface Properties of Anatase TiO2 Nanowire Films Grown from a Fluoride‐Containing Solution

Controlling the surface chemistry of nucleating seeds during wet‐chemical synthesis allows for the preparation of morphologically well‐defined nanostructures. Synthesis conditions play a key role in the surface properties, which directly affect the functional properties of the material. Therefore, it is important to establish post‐synthesis treatments to facilitate the optimization of surface properties with respect to a specific application, without losing the morphological peculiarity of the nanostructure. We studied the surface properties of highly crystalline and porous anatase TiO₂ nanowire (NW) electrodes, grown by chemical‐bath deposition in fluoride‐containing solutions, using a combined electrochemical and spectroscopic approach. As‐deposited films showed low capacity for catechol adsorption and a poor photoelectrocatalytic activity for water oxidation. Mild thermal annealing at 200 °C resulted in a significant improvement of the electrode photoelectrocatalytic activity, whereas the bulk properties of the NWs (crystal structure, band‐gap energy) remained unchanged. Enhancement of the functional properties of the material is discussed on the basis of adsorption capacity and electronic properties. The temperature‐induced decrease of recombination centers, along with the concomitant increase of adsorption and reaction sites upon thermal annealing are called to be responsible for such improved performance.     

Al-MCM-41 负载离子液体双酸位催化剂及制备生物柴油

采用不同硅铝比的MCM-41负载离子液体,制备得到一系列负载型双酸位催化剂,并用XRD、FTIR、N₂-吸脱附、热重分析及TEM对其进行表征,以大豆油与甲醇的酯交换反应为探针实验考察了其催化活性.结果表明,离子液体成功固载于介孔分子筛并能保持其介孔结构,且在酯交换反应中表现出良好的反应活性.在ILs负载量为30%,醇油物质的量的比为36:1,140 ℃下反应5 h,生物柴油收率在90%以上;而分子筛中Al的引入为活性组分离子液体构建了有益的酸环境,促进了其催化活性的提高;与均相离子液体相比,负载型催化剂又能明显提高生物柴油的收率,且回收利用4次后,生物柴油收率仍接近88%.     

加热方式及原料配比对介孔CeO2结构及其光催化性能的影响

以P123（聚环氧乙烷-聚环氧丙烷-聚环氧乙烷三嵌段共聚物）为模板剂,Ce（NO₃）₃为反应原料,通过考察加热方式、加热温度、原料配比等因素,合成了结构性能较好、表面羟基含量较高的介孔CeO₂材料。利用XRD,N₂吸附-脱附,TEM,Raman,FT-IR等技术对合成样品的结构性能进行了表征,结果表明,当P123与Ce（NO₃）₃物质的量之比为1：10,在110℃水热下合成的CeO₂结构性能最好。以酸性橙7（AO7）为探针分子,对合成介孔CeO₂的光催化性能进行评价。光催化结果证明,由于表面羟基含量较高、介孔及氧缺位的形成,所合成结构性能较好的CeO₂,利用可见光可彻底催化降解溶液中的AO7。     

Electrochemical Characteristics of Discrete,Uniform, and Monodispersed Hollow Mesoporous Carbon Spheres in Double‐Layered Supercapacitors

Core–shell‐structured mesoporous silica spheres were prepared by using n‐octadecyltrimethoxysilane (C18TMS) as the surfactant. Hollow mesoporous carbon spheres with controllable diameters were fabricated from core–shell‐structured mesoporous silica sphere templates by chemical vapor deposition (CVD). By controlling the thickness of the silica shell, hollow carbon spheres (HCSs) with different diameters can be obtained. The use of ethylene as the carbon precursor in the CVD process produces the materials in a single step without the need to remove the surfactant. The mechanism of formation and the role played by the surfactant, C18TMS, are investigated. The materials have large potential in double‐layer supercapacitors, and their electrochemical properties were determined. HCSs with thicker mesoporous shells possess a larger surface area, which in turn increases their electrochemical capacitance. The samples prepared at a lower temperature also exhibit increased capacitance as a result of the Brunauer–Emmett–Teller (BET) area and larger pore size.