Excellent degradation performance of azo dye by metallic glass/titanium dioxide composite powders

The metallic glass/titanium dioxide powders (MG/TiO₂) with enhanced photocatalytic oxidation activity were synthesized, which exhibit a higher efficiency in decolorizing methylene blue solutions (MB). Compared with the pure TiO₂ and crystalline alloy/TiO₂ (CA/TiO₂) under the same circumstances, its degradation rate was 60 % and 30 % higher, respectively. Furthermore, compared with the CA/TiO₂, the MG/TiO₂ photocatalytic rate was three times faster when decolorizing MB. Considering the excellent intrinsic high-performance photocatalytic degradation under visible light irradiation, these novel powders were proven to have potential applications in water purification industry.     

A Triazatruxene‐Based Glycocluster as a Fluorescent Sensor for Concanavalin A

A new triazatruxene‐based fluorescent glycocluster has been designed, synthesized, and fully characterized by NMR spectroscopy and mass spectrometry. Furthermore, its specific and selective binding properties with concanavalin A (Con A) have been investigated by fluorescence spectroscopy, circular dichroism (CD) spectroscopy, and turbidity assay. The obtained results showed that the multivalent mannose‐modified triazatruxene exhibited specific binding with Con A, but no binding to peanut agglutinin (PNA) lectin or bovine serum albumin (BSA), corresponding to a two‐orders‐of‐magnitude higher affinity than that of monovalent mannose ligands. Most interestingly, a fluorescence enhancement of the triazatruxene‐based glycocluster was observed upon binding with Con A because of hydrophobic interactions involving sites close to the triazatruxene moiety. Furthermore, the inhibitory ability of the triazatruxene‐based glycocluster against ORN178‐ induced haemagglutination has been investigated by haemagglutination inhibition assay. The results indicated selective binding with ORN178.     

Preparation and characterization of ZrCO/C composite aerogels

Zr-containing organic aerogels were synthesized by ligand substitution reaction of polyzirconoxone and 2, 4-dihydroxybenzoic acid, followed by polymerization with formaldehyde, and then supercritical drying using CO₂. After carbonization and carbothermal reduction under an argon atmosphere, ZrCO/C composite aerogels with controllable zirconium content (47.8–78.6 wt%) were obtained. The carbothermal reduction was substantially completed at 1,500 °C, and the obtained ZrCO/C composite aerogels exhibit low oxygen contents (9.4–6.7 wt%) and high surface areas (589–147 m²/g). Pore morphologies of the ZrCO/C composite aerogels were investigated in detail by nitrogen sorption measurements, scanning electron microscopy and its associated energy-dispersive X-ray microanalysis measurements. The results show that the aerogels are composed of carbon framework and Zr-conglomerations, and the surface area of aerogel is severely affected by its zirconium content. The presence of reductive ZrC crystals can greatly enhance the oxidation resistance ability of amorphous carbon framework and prevent collapse.     

Self‐Assembled Poly(N‐methylaniline)–Lignosulfonate Spheres: From Silver‐Ion Adsorbent to Antimicrobial Material

Self‐assembled poly(N‐methylaniline)–lignosulfonate (PNMA–LS) composite spheres with reactive silver‐ion adsorbability were prepared from N‐methylaniline by using lignosulfonate (LS) as a dispersant. The results show that the PNMA–LS composite consisted of spheres with good size distribution and an average diameter of 1.03–1.27 μm, and the spheres were assembled by their final nanofibers with an average diameter of 19–34 nm. The PNMA–LS composite spheres exhibit excellent silver‐ion adsorption; the maximum adsorption capacity of silver ions is up to 2.16 g g^?1 at an adsorption temperature of 308 K. TEM and wide‐angle X‐ray results of the PNMA–LS composite spheres after absorption of silver ions show that silver ions are reduced to silver nanoparticles with a mean diameter of about 11.2 nm through a redox reaction between the PNMA–LS composite and the silver ions. The main adsorption mechanism between the PNMA–LS composite and the silver ions is chelation and redox adsorption. In particular, a ternary PNMA–LS–Ag composite achieved by using the reducing reaction between PNMA–LS composite spheres and silver ions can be used as an antibacterial material with high bactericidal rate of 99.95 and 99.99 % for Escherichia coli and Staphylococcus aureus cells, respectively.     

Fast Reductive Amination by Transfer Hydrogenation “on Water”

Reductive amination of various ketones and aldehydes by transfer hydrogenation under aqueous conditions has been developed, by using cyclometallated iridium complexes as catalysts and formate as hydrogen source. The pH value of the solution is shown to be critical for a high catalytic chemoselectivity and activity, with the best pH value being 4.8. In comparison with that in organic solvents, the reductive amination in an aqueous phase is faster, and the molar ratio of the substrate to the catalyst (S/C) can be set as high as 1×10⁵, the highest S/C value ever reported in reductive amination reactions. The catalyst is easy to access and the reaction is operationally simple, allowing a wide range of ketones and aldehydes to react with various amines in high yields. The protocol provides a practical and environmental friendly new method for the synthesis of amine compounds.     

Dynamic Electrosorption Analysis as an Effective Means to Characterise the Structure of Bulk Graphene Assemblies

Restacking of graphene sheets to a graphite‐like structure is a prevailing problem that is known to compromise the performance of individual graphene sheets in an assembled bulk form. To address this common problem efficiently and monitor the structure and quality of graphene products comprehensively, it is highly desirable to develop reliable metrology techniques for characterising graphene‐based materials on a bulk assembly level and in a quantitative manner. Here, by revisiting the physicochemical principle of electrosorption, we propose a simple electrochemical approach, namely dynamic electrosorption analysis (DEA), as an easily accessible and effective technique for evaluation of the self‐stacking behaviour of graphene. Taking multilayered chemically converted graphene films as a model, we demonstrate that the DEA technique can effectively reveal very subtle variation in accessible surface area and pore size of graphene assemblies in the liquid phase and thus can provide useful insights to the experimental design relating to restacking control. This work also reveals the huge effect some routine processing conditions, such as heat treatment and drying, can have on the structure and performance of graphene‐based bulk materials, providing useful guidance for future manufacturing of this class of materials.     

Distinct Stepwise Reduction of a Nickel?Nickel‐Bonded Compound Containing an α‐Diimine Ligand: From Perpendicular to Coaxial Structures

A nickel? nickel‐bonded complex, [{Ni(μ‐L^.?)}₂] ( 1 ; L=[(2,6‐iPr₂C₆H₃)NC(Me)]₂), was synthesized from reduction of the LNiBr₂ precursor by sodium metal. Further controllable reduction of 1 with 1.0, 2.0 and 3.0 equiv of Na, respectively, afforded the singly, doubly, and triply reduced compounds [Na(DME)₃] ? [{Ni(μ‐L^.?)}₂] ( 2 ; DME=1,2‐dimethoxyethane), [Na(Et₂O)]Na[(L^.?)Ni? NiL^2?] ( 3 ), and [Na(Et₂O)]₂Na[L^2?Ni? NiL^2?] ( 4 ). Here L represents the neutral ligand, L^.? denotes its radical monoanion, and L^2? is the dianion. All of the four compounds feature a short Ni? Ni bond from 2.2957(6) to 2.4649(8) Å. Interestingly, they display two different structures: the perpendicular ( 1 and 2 ) and the coaxial ( 3 and 4 ) structure, in which the metal? metal bond axis is perpendicular to or collinear with the axes of the α‐diimine ligands, respectively. The electronic structures, Ni? Ni bonding nature, and energetic comparisons of the two structure types were investigated by DFT computations.     

固相萃取-液相色谱-串联质谱法测定水果和土壤中四螨嗪残留量

建立了水果和土壤样品中四螨嗪的液相色谱-电喷雾串联质谱检测方法。水果或土壤样品用丙酮提取,经弗罗里硅土柱净化,以Agilent ZORBAX SB-C18色谱柱分离,以电喷雾电离串联质谱正离子多反应监测模式进行测定。对四螨嗪在水果和土壤中在4个不同添加水平下的回收率进行了测定,结果表明,四螨嗪在柑橘(全果)中的添加回收率为86.9%～93.1%(RSD为7.4%～9.4%),在苹果中的添加回收率为84.1%～95.1%(RSD为5.9%～9.7%),在葡萄中的添加回收率为88.8%～93.7%(RSD为8.0%～10.1%),在梨中的添加回收率为88.6%～96.1%(RSD为7.0%～10.2%),在土壤中的添加回收率为83.0%～96.8%(RSD 6.7%～12%)。该方法满足农药残留检测要求,适用于水果和土壤中四螨嗪残留的检测。     

钪元素对AB2型合金Zr1-xScxMn0.6V0.2Ni1.2Co0.1（x=0～1）储氢和电化学性能的影响

用真空电弧熔炼方法制备了Zr1-xScxMn0.6V0.2Ni1.2Co0.1(x=0～1)AB2型储氢合金,研究了Sc元素替代Zr对合金的微观组织结构、气态储氢及电化学性能的影响。研究结果表明,Zr1-xScxMn0.6V0.2Ni1.2Co0.1合金主要是由FCC型C15相、CsCl型结构的(ScZr)Ni相和少量的Ni10Zr7相组成,随Sc含量的增加,C15相丰度逐渐减小,(ScZr)Ni相丰度逐渐增加,当x=0.2时Ni10Zr7相基本消失;Sc元素对合金的首次气态吸氢动力学行为影响较大,随Sc含量的增加,合金吸氢动力学性能逐渐变缓,但吸氢容量逐渐提高,直至达x=1.0时的最大吸氢量1.87%;Sc元素对合金吸氢PCT曲线平衡氢压的影响规律不明显,随Sc含量增加,合金氢化物的形成焓ΔH从-26.66 kJ.mol-1逐渐减小到-8.14 kJ.mol-1。Sc元素的加入可明显改善合金电极的活化性能,提高放电容量,随Sc含量的增加,合金电极最大放电容量从x=0时的350.3 mAh.g-1增加到x=1时的429.8 mAh.g-1,呈先减小后增大的趋势,但电极容量的保持率S100随Sc含量增加而快速下降。     

电场对金属串配合物M3(dpa)4Cl2 (M=Co,Rh, Ir; dpa=dipyridylamide)结构的影响

应用密度泛函理论PBE0 方法研究具有分子导线潜在应用的金属串配合物M₃(dpa)₄Cl₂ (1: M=Co, 2: M=Rh, 3: M=Ir; dpa=dipyridylamide)在电场作用下的几何和电子结构. 结果表明: 配合物基态均是二重态. 1和2的M₃⁶⁺金属链形成三中心三电子σ键, 3 中M₃⁶⁺形成三中心四电子σ键且存在弱的δ键. 随金属原子周期数增大其M―M键增强、LUMO与HOMO能隙减小、金属原子的反铁磁耦合减弱以至消失且自旋密度向配体的离域增强. 在Cl4→Cl5 电场作用下, 低电势端的M3－Cl5 键缩短, 高电势端的M2―Cl4 键增长, M―M平均键长略为缩短, M―M键增强, 有利于分子线的电子传递; 分子能量降低, 偶极矩线性增大. 低电势端Cl5的负电荷向高电势端Cl4 转移, 且3 中金属原子的正电荷由高电势端向低电势端的转移较明显, 自旋电子由低电势端向高电势端金属原子移动, 但桥联配体dpa^-与M和Cl 所在的分子轴间没有电荷转移. 电场使LUMO与HOMO能隙减小, 有利于分子的电子输运. 随金属原子周期数增大, 电场作用下M―M平均键长变化减小, LUMO、HOMO的能级交错现象减少.