Modified hydrothermal fabrication of a CoS2–graphene hybrid with improved photocatalytic performance

CoS₂ and a CoS₂–graphene composite were synthesized via a facile sonochemical and hydrothermal method. As-prepared samples were characterized by X-ray diffraction, scanning electron microscopy with energy-dispersive X-ray analysis, transmission electron microscopy, and UV-vis diffuse reflectance spectroscopy. The CoS₂–graphene composites exhibited high dye adsorption, extended light absorption, and efficient charge separation properties. Hence, for photodegradation of methylene blue (MB), significant enhancement of the reaction rate was observed for CoS₂–graphene compared to pure CoS₂. The high activity can be attributed to positive synergetic effects between CoS₂ and graphene. The excellent photoinduced charge separation and observed red shift make these hybrid materials potential candidates for the development of high-performance next-generation photocatalyst materials.     

元青花《昭君出塞》罐艺术特征与主题思想研究

"昭君出塞"故事源于汉代,绵延流传,元青花《昭君出塞》罐表现的即为"昭君出塞"故事题材。元青花《昭君出塞》罐具有鲜明的艺术特征,同时,亦具有丰富而深邃的主题思想内涵。     

Molecular design of deep blue fluorescent emitters with 20% external quantum efficiency and narrow emission spectrum

A thermally activated delayed fluorescent (TADF) emitter, 2,7-bis(9,9-dimethylacridin-10(9H)-yl)-9,9-dimethyl-9H-thioxanthene 10,10-dioxide (DMTDAc), was developed as a deep blue TADF emitter using a rigid 9,9-dimethyl-9H-thioxanthene 10,10-dioxide (DMTD) acceptor and an acridine donor. The rigid DMTD acceptor narrowed emission spectrum of DMTDAc by interlocking two phenyl units of diphenylsulfone. A deep blue TADF device with an external quantum efficiency close to 20% with a deep blue color coordinate of (0.15,0.13) was provided using the DMTDAc TADF emitter.     

水热法制备钒酸铋及可见光催化降解亚甲基蓝溶液研究

利用水热法制备了BiVO4粉体,并通过X射线衍射(XRD)、扫描电镜(SEM)、紫外一可见漫反射光谱(DRS)等对催化剂进行了表征。以制备的BiVO4为催化剂,考察了可见光照射下其对亚甲基蓝的降解效果。研究结果表明对初始质量浓度为10 mg/L的亚甲基蓝溶液50 mL,BiVO4加入量为0.6 g/L,经500 W氙灯(可见光)照射6 h后,亚甲基蓝的脱色率可达64%。     

Visual abstraction of dynamic network via improved multi-class blue noise sampling

Massive sequence view (MSV) is a classic timeline-based dynamic network visualization approach. However, it is vulnerable to visual clutter caused by overlapping edges, thereby leading to unexpected misunderstanding of time-varying trends of network communications. This study presents a new edge sampling algorithm called edge-based multi-class blue noise (E-MCBN) to reduce visual clutter in MSV. Our main idea is inspired by the multi-class blue noise (MCBN) sampling algorithm, commonly used in multi-class scatterplot decluttering. First, we take a node pair as an edge class, which can be regarded as an analogy to classes in multi-class scatterplots. Second, we propose two indicators, namely, class overlap and inter-class conflict degrees, to measure the overlapping degree and mutual exclusion, respectively, between edge classes. These indicators help construct the foundation of migrating the MCBN sampling from multi-class scatterplots to dynamic network samplings. Finally, we propose three strategies to accelerate MCBN sampling and a partitioning strategy to preserve local high-density edges in the MSV. The result shows that our approach can effectively reduce visual clutters and improve the readability of MSV. Moreover, our approach can also overcome the disadvantages of the MCBN sampling (i.e., long-running and failure to preserve local high-density communication areas in MSV). This study is the first that introduces MCBN sampling into a dynamic network sampling.     

Synthesis,characterisation and structural studies of Rb x Mn[Fe(CN)6]

We present the synthesis and detailed characterisation of the Rb _x Mn[Fe(CN)₆] compound. The composition of the material significantly depends on the applied preparative conditions. Analysis of spectroscopic results (EDX,?Raman) and X-ray powder diffraction data yielded a further assessment of the difference in structural features. The characteristic individual magnetic behaviour, as well as the metal-to-metal charge transfer capabilities of the various samples, could be related to significant changes within the structures that appear to be associated with the synthetic method used.     

Electrochemical growth of tin(II) oxide films: Application in photocatalytic degradation of methylene blue

We have investigated the semiconducting and photoelectrochemical properties of SnO films grown potentiostatically on tin substrate. The oxide is characterized by X-ray diffraction, scanning electron microscopy and Raman spectroscopy. The anodic process corresponds to the formation of SnO·nH₂O pre-passive layer that is removed upon increasing potential due to surface etching at the metal/oxide interface. SnO films deposited for long durations (>50 mn) are uniform and well adhered; they thicken up to ~50 nm by diffusion-controlled process and the growth follows a direct logarithmic law. The thickness is determined by coulometry and the X-ray diffraction indicates the tetragonal SnO phase (SG: P4/mmm) with a crystallite size of 32 nm. The Mott–Schottky plot is characteristic of n type conductivity with an electrons density of 5.72×10¹⁸ cm⁻³, a flat band potential of −0.09 V_SCE and a depletion width of ~10 nm. The valence band, located at 5.91 eV below, vacuum is made up of hybridized O²⁻:2p Sn²⁺:5s while the conduction band (4.45 eV) derives from Sn²⁺:5p orbital. The electrochemical impedance spectroscopy (EIS) measured in the range (10⁻²–10⁵ Hz) shows the contribution of the bulk and grain boundaries. The energy band diagram predicts the photodegradation of methylene blue on SnO films. 67% of the initial concentration (10 mg L⁻¹) disappears after 3 h of exposure to visible light (9 mW cm⁻²) with a quantum yield of 0.072.     

Cr2WO6 nanoparticles prepared by hydrothermal assisted method with selective adsorption properties for methylene blue in water

Cr₂WO₆ nanocrystallites were prepared using a facile hydrothermal assisted process. The microstructures and preferential adsorption performance for methylene blue (MB) of the prepared nanoparticles were investigated using a solid state reaction resulted in Cr₂WO₆ crystallites as a baseline. Their structural information were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive spectrometer, transmission electron microscopy, N₂–sorption BET surface area, thermogravimetric and differential scanning calorimeters. Results show that the Cr₂WO₆ nanocrystallines with ~50 nm in size are achieved by calcination at 650 °C for only 2 h using a hydrothermal product as precursor, while the micrometer sized Cr₂WO₆ crystallites synthesized by the solid state reaction at higher temperature (950 °C) for at least 20 h. For the as-prepared Cr₂WO₆ nanocrystallines, the adsorption performance were tested using methyl orange (MO), Rhodamine B (RhB) and methylene blue (MB). The adsorption ability was found to be in the order of MB>>RhB>MO owing to electrostatic interactions between the adsorbent and the dye. Results of this study provide a kind of promising alternative adsorbent for color removal from industrial wastewaters.