Dye-sensitized solar cells based on ordered titanate nanotube films fabricated by electrophoretic deposition method

Dye-sensitized solar cells (DSSCs) are fabricated based on ordered titanate nanotube (TNT) films obtained by electrophoretic deposition (EPD) method. Calcination temperatures show a great influence on the performance of TNT solar cells. At 300 °C, the cells exhibit very low photo-electric conversion efficiency. At 400 °C, the efficiency obviously increases. At 600 °C, the cells show the highest efficiency, which is higher than the efficiency of the cells made from commercial-grade Degussa P25 TiO₂ nanoparticles (P25).     

Monodisperse,submicrometer-scale platinum colloidal spheres with high electrocatalytic activity

Monodisperse, submicrometer-scale platinum (Pt) colloidal spheres were prepared through a simple direct chemical reduction of p-phenylenediamine (PPD)-chloroplatinic acid (H₂PtCl₆) coordination polymer colloids. It was found that the prepared Pt colloids had the similar size and morphology with their coordination polymer precursors, and the prepared Pt colloids with rough surfaces were three-dimensional (3D) structured assemblies of high-density small Pt nanoparticles. The electrochemical experiments confirmed that the prepared Pt colloids possessed a high electrocatalytic activity towards mainly four-electron reduction of dioxygen to water, making the prepared Pt colloids potential candidates for the efficient cathode material in fuel cells.     

Electrochemical-reduced graphene oxide-modified carbon fiber as Pt–Au nanoparticle support and its high efficient electrocatalytic activity for formic acid oxidation

A simple electrochemical approach is developed to prepare reduced graphene oxide (RGO)-wrapped carbon fiber (CF) as a novel support for Pt–Au nanocatalysts. The obtained composite electrodes have been characterized by scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (EDX), thermal gravimetric analysis (TGA), and electrochemical methods. SEM images reveal that the Pt–Au nanoparticles deposited on RGO-wrapped CF (RGO/CF) electrode display smaller particle size and more uniform dispersion than those on the bare CF electrode. Cyclic voltammetry, linear sweep voltammetry, chronoamperometry, chronopotentiometry, Tafel plots, and electrochemical impedance spectroscopy (EIS) analyses demonstrate that the introduced RGO on CF electrode surface is beneficial to the dispersion of Pt–Au nanoparticles, as a consequence, to the enhancement of the electrocatalytic activity and the antipoisoning ability of Pt–Au towards formic acid electrooxidation.     

A One-pot Approach to Ethyl 1,4,5-Triaryl-lH-pyrazole-3- carboxylates via an Improved Claisen Condensation- Knorr Reaction Sequence

A one-pot approach to ethyl 1,4,5-triaryl-lH-pyrazole-3-carboxylates has been developed in moderate to high yields. The tert-BuOLi-mediated Claisen condensation of 1,2-diarylethanones and ethyl oxalyl chloride efficiently provided the enolized lithium salts of ethyl 2,4-dioxo-3,4-diarylbutanoates, which in situ reacted with arylhydrazine hydrochlorides via a hydrochloric acid-promoted Knorr reaction to produce the exquisite triarylpyrazole-3- carboxylates. The procedure promises a convenient access to this highly crowded framework for drug discovery.     

Nafion–graphene nanocomposite film as enhanced sensing platform for ultrasensitive determination of cadmium

In this work, an ultrasensitive platform for the detection of cadmium (Cd²⁺) combining the nafion–graphene nanocomposite film with differential pulse anodic stripping voltammetry (DPASV) analysis was presented. It is found that this sensing platform exhibits enhanced response to the determination of the Cd²⁺ and has been used to determine the Cd²⁺ in real sample with good recovery.     

A Note on time regularity of generalized Ornstein–Uhlenbeck processes with cylindrical stable noise

A necessary and sufficient condition of càdlàg modification of Ornstein–Uhlenbeck process with cylindrical stable noise in a Hilbert space is given in this Note. Applying this result, some questions in Time irregularity of generalized Ornstein–Uhlenbeck processes [C. R. Acad. Sci. Paris, Ser. I 348 (2010) 273–276] and Structural properties of semilinear SPDEs driven by cylindrical stable process [Probab. Theory Related Fields 149 (2011) 97–137] are answered.     

Synthesis of well‐defined pH‐responsive PPEGMEA‐g‐P2VP double hydrophilic graft copolymer via sequential SET‐LRP and ATRP

A series of well‐defined double hydrophilic graft copolymers containing poly(poly(ethylene glycol) methyl ether acrylate) (PPEGMEA) backbone and poly(2‐vinylpyridine) (P2VP) side chains were synthesized by successive single electron transfer living radical polymerization (SET‐LRP) and atom transfer radical polymerization (ATRP). The backbone was first prepared by SET‐LRP of poly(ethylene glycol) methyl ether acrylate (PEGMEA) macromonomer using CuBr/tris(2‐(dimethylamino)ethyl)amine as catalytic system. The obtained homopolymer then reacted with lithium diisopropylamide and 2‐chloropropionyl chloride at ?78 °C to afford PPEGMEA‐Cl macroinitiator. poly(poly(ethylene glycol) methyl ether acrylate)‐g‐poly(2‐vinylpyridine) double hydrophilic graft copolymers were finally synthesized by. ATRP of 2‐vinylpyridine initiated by PPEGMEA‐Cl macroinitiator at 25 °C using CuCl/hexamethyldiethylenetriamine as catalytic system via the grafting‐ from strategy. The molecular weights of both the backbone and the side chains were controllable and the molecular weight distributions kept relatively narrow (M_w/M_n ≤ 1.40). pH‐Responsive micellization behavior was investigated by ¹H NMR, dynamic light scattering, and transmission electron microscopy and this kind of double hydrophilic graft copolymer aggregated to form micelles with P2VP‐core while pH of the aqueous solution was above 5.0. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Atomic structure of Co92−xBxTa8 glassy alloys studied by ab initio molecular dynamics simulations

The ab initio molecular dynamics simulations were adopted to study the atomic structures of Co_92−xB_xTa₈ (x = 30, 32.5, 35, 37.5, at%) glassy alloys. The results showed that the local packing of B-centered clusters was more efficient than that of Co- and Ta-centered clusters. It was also found that B-centered clusters were the primary structure-forming clusters. The Kasper polyhedra with a Voronoi index of <0 3 6 0> and <0 2 8 0> are dominant in B-centered clusters. The <0 3 6 0> clusters could especially be formed into a robust network structure, which plays a key role in the increase of mechanical properties. Such a network structure has a higher activation barrier for structural rearrangement and a larger resistance to plastic flow. Thus, the increase in the fraction of <0 3 6 0> with B content would result in an increase in yield strength, as well as a sharp decrease in compressive plasticity.     

Influence of Microbial Agglomerated Particles on the Performance of Free-Space Quantum Communication

Journal of Russian Laser Research - Quantum satellite communication has advantages of reliability and unconditional safety; it is very important in the field of national military security. When...