Controlled Synthesis of Ni-Doped MoS2 Hybrid Electrode for Synergistically Enhanced Water-Splitting Process

The development of high-efficiency, low-cost, and earth-abundant electrocatalysts for overall water splitting remains a challenge. In this work, Ni-modified MoS₂ hybrid catalysts are grown on carbon cloth (Ni-Mo-S@CC) through a one-step hydrothermal treatment. The optimized Ni-Mo-S@CC catalyst shows excellent hydrogen evolution reaction (HER) activity with a low overpotential of 168 mV at a current density of 10 mA cm⁻² in 1.0 m KOH, which is lower than those of Ni-Mo-S@CC (1:1), Ni-Mo-S@CC (3:1), and pure MoS₂. Significantly, the Ni-Mo-S@CC hybrid catalyst also displays outstanding oxygen evolution reaction (OER) activity with a low overpotential of 320 mV at a current density of 10 mA cm⁻², and remarkable long-term stability for 30 h at a constant current density of 10 mA cm⁻². Experimental results and theoretical analysis based on density functional theory demonstrate that the excellent electrocatalytic performance can be attributed mainly to the remarkable conductivity, abundant active sites, and synergistic effect of the Ni-doped MoS₂. This work sheds light on a unique strategy for the design of high-performance and stable electrocatalysts for water-splitting electrolyzers.     

A high accuracy flow segmentation method in crowded scenes based on streakline

Flow segmentation based on similar motion patterns in crowded scenes remains an open problem in computer vision due to inherent complexity and vast diversity found in such scenes. To solve this problem, the streakline framework based on Lagrangian fluid dynamics had been proposed recently. However, this framework computed optical flow field using conventional optical flow method (Lucas Kanade method) which has poor anti-interference performance, and serious deviation would be brought to the computation of optical flow field. Moreover, our experimental results show that using the formulation of streak flow similarity in this framework can result in incorrect flow segmentation. Therefore, we combine this framework with a high accurate variational model, and modify the corresponding formulation of streak flow similarity after analyzing the streakline framework in detail. Finally, an improved method is proposed to solve flow segmentation in crowded scenes. Experiments are done to compare these two methods and results verify the validity and accuracy of our method.     

Easy One‐Pot Synthesis of 1‐Monosubstituted Aliphatic 1,2,3‐Triazoles from Aliphatic Halides,Sodium Azide and Propiolic Acid by a Click Cycloaddition/Decarboxylation Process

1‐Monosubstituted aliphatic 1,2,3‐triazoles were synthesized by a one‐pot reaction from aliphatic halides (Cl and Br), sodium azide and propiolic acid. The yields ranged from moderate to good. The reaction was easily carried out in DMF with Cs₂CO₃ at 100°C by copper‐catalyzed click cycloaddition/decarboxylation.     

Synthesis and Characterization of Iron Nanowires

The iron nanowires can be fabricated via the process in which sodium borohydride reduces iron salts in external magnetic field. The iron nanowires are found to be covered by passivated layers of iron oxide which prevent the oxidation of iron nanowires. In this process, the boron will include in iron nanowires. The average length and diameter of iron nanowires is around 1.2 micrometers and 60 nanometers, respectively. According to ICP results, the contents of B and Fe are about 1.98 wt% and 87.04 wt%, respectively, in iron nanowires. A wide variety of equipment is used to investigate the morphological, microchemical, and structural characteristics of the newly synthesized iron nanowires ––– e.g., XRD, FE‐SEM, HR‐TEM, VSM and XANES. XANES analysis indicates the boron in iron nanowires exists in the form of B₂O₃. The saturation magnetization and the coercive force of iron nanowires are 157.93 emu/g and 9.74 Oe, respectively. In‐situ images of synthesized iron nanowires during reduction process in magnetic field are observed by NSRRC transmission X‐ray microscope. Thus, this study develop a novel process to produce iron nanowires with large quantitates and can control its length and diameter by various the concentration of precursors for various applications.     

Self‐assembly of Carbon Particles as a Heat Sink Coating to Promote Radiative Cooling

Novel composite carbon particles are developed that can self‐assemble as a coating on a substrate without a binder. These carbon particles were used as a coating to enhance thermal dissipation and their thermal conductivity, surface emissivity and cooling performance were measured. Carbon particles with both thiol and epoxy functional groups self‐assembled to form a coating on the surface of a heat sink without a binder, which greatly improved the thermal conductivity of the coating. Coating a heat sink with the carbon particles yielded a higher thermal conductivity and emissivity than could be obtained with the addition of binder in the conventional approach, and significantly enhanced the cooling performance. In addition, the cooling performance of the carbon nanotube outperformed all other particles when coated on a substrate, because it had the highest thermal conductivity and good radiation emissivity. We developed an equation to describe the various parameters affecting the cooling performance of the thermally dissipative coating. This equation was confirmed by the experimental data.     

Decontamination of radionuclides on construction materials

A wide variety of materials can become contaminated by radionuclides, either from a terrorist attack or an industrial or nuclear accident. The final disposition of these materials depends, in large part, on the effectiveness of decontamination measures. This study reports on investigations into the decontamination of a selection of building materials. The aim has been to find an effective, easy-to-use and inexpensive decontamination system for radionuclides of cesium and cobalt, considering both the chemical and physical nature of these potential contaminants. The basic method investigated was surface washing, due to its ease and simplicity. In the present study, a basic decontamination formulation was modified by adding isotope-specific sequestering agents, to enhance the removal of cesium(I) and cobalt(II) from such construction materials as concrete, marble, aluminum and painted steel. Spiking solutions contained ¹³⁴Cs or ⁶⁰Co, which were prepared by neutron activation in the SLOWPOKE-2 nuclear reactor facility at the Royal Military College of Canada. Gamma spectroscopy was used to determine the decontamination efficiency. The results showed that the addition of sequestering agents generally improved the radiological decontamination. Although the washing of both cesium and cobalt from non-porous materials, such as aluminum and painted steel, achieved a 90–95 % removal, the decontamination of concrete and marble was more challenging, due to the porous nature of the materials. Nevertheless, the removal efficiency from 6-year-old concrete increased from 10 % to approximately 50 % for cobalt(II), and from 18 to 55 % for cesium(I), with the use of isotope binding agents, as opposed to a simple water wash.     

Preparation of Unconventional Dendrimers that Contain Rigid NH?Triazine Linkages and Peripheral tert‐Butyl Moieties for CO2‐Selective Adsorption

Three unconventional dendrimers that contained rigid NH? triazine linkages and peripheral tert‐butyl moieties were prepared by using a convergent approach and characterized by ¹H and ¹³C NMR spectroscopy, mass spectrometry, and elemental analysis. Based on a thermogravimetric analysis study, these dendrimers were observed to display thermal stability at about 300 °C. The NH? triazine moiety, which possessed protonated and proton‐free nitrogen sites (like the imidazole unit), displayed the capture of polarizable CO₂ molecules through hydrogen‐bond and/or dipole–quadrupole interactions. In addition, the adsorption of various amounts of CO₂ and N₂ at different pressures suggests that the dendritic pores, which arise from the stacking of the middle co‐planar and rim protuberant dendrimers, G _n ‐N～N‐G _n (n=1–3), either swell or shrink at high pressure, thus indicating that these dendrimers may have a breathing ability.     

Facile Self‐Assembly Synthesis of PdPt Bimetallic Nanotubes with Good Performance for Ethanol Oxidation in an Alkaline Medium

PdPt bimetallic nanotubes were prepared by the self‐assembly of Pt and Pd on Te nanowires at room temperature. The morphologies of the as‐prepared PdPt nanotubes were investigated by scanning electron microscopy and transmission electron microscopy, and the results display a large amount of PdPt bimetallic nanotubes with a diameter of 10–20 nm and a length of several micrometers. The composition and structure of the nanotubes were characterized by X‐ray diffraction, high‐resolution transmission electron microscopy, scanning transmission electron microscopy, and energy spectrum analysis, and the results display uniform compositional distributions of both elements (Pd and Pt). The mechanism of the formation of the nanotube structure was supposed. The electrocatalytic performance of PdPt nanotubes were studied by cyclic voltammetry and chronoamperometry. Electrochemical results show that the as‐prepared PdPt nanotube catalysts have not only high activity but also good stability for ethanol oxidation in alkaline medium.