单层MXene纳米片Ti2N电磁特性的过渡金属(Sc、V、Zr)掺杂效应

二维材料MXene纳米片由于具有较大的比表面积和较高的电子迁移率而受到广泛的关注。本文采用基于密度泛函理论的第一性原理计算,对单层MXene纳米片Ti₂N电磁特性的过渡金属(Sc、V、Zr)掺杂效应进行了系统研究。结果表明,所有过渡金属掺杂体系结合能均为负值,结构均稳定;其中Ti₂N-Sc体系的形成能为-2.242 eV,结构更易形成,且保持稳定;掺杂后Ti₂N-Sc、Ti₂N-Zr体系磁矩增大;此外,Ti₂N-Sc体系中保留了较高的自旋极化率,达到84.9%,可预测该体系在自旋电子学中具有潜在的应用价值。     

SAPO-34提升铁钒基催化剂抗碱性能研究

采用浸渍法制备Fe-VO_x/SAPO-34和Fe-VO_x/TiO₂脱硝催化剂,探究SAPO-34分子筛与TiO₂两种载体负载铁钒基氧化物催化活性及抗碱性能的差异。借助X射线衍射(XRD)、X射线光电子能谱(XPS)、氨气程序升温脱附(NH₃-TPD)、氢气程序升温还原(H₂-TPR)、原位红外漫反射(in-situ DRIFTs)等表征手段对催化剂的骨架结构、表面物化性质、氧化还原能力以及对反应气体的吸脱附情况进行分析。结果表明:SAPO-34分子筛内部特定的孔道结构和稳定的骨架,有利于活性组分在载体上均匀分散,降低碱金属对表面活性中心的物理覆盖作用;同时其表面丰富的酸位点能够作为碱金属捕获位,保护催化剂表面的活性中心,保证催化剂的吸附-反应过程能够正常进行,从而使Fe-VO_x/SAPO-34表现出良好的抗碱金属能力。     

直接碳燃料电池燃料的研究进展

直接碳燃料电池(DCFC)是一种清洁高效利用碳资源发电的装置。其因能量转换率高,对环境污染小,燃料选择范围广等优点获得了越来越多的关注。DCFC的性能与使用的燃料密切相关,为了探究燃料对DCFC的影响,本文分别阐述了石墨、炭黑、中密度纤维板、生物质、煤、活性炭的特性及改性方法,分析讨论了燃料表面含氧官能团以及燃料中的金属催化剂对阳极电化学反应的促进作用,发现燃料表面化学性质要比比表面积更加重要。同时,本文也提出了对生物质这一优良的可再生资源的期待,为未来DCFC燃料的发展提供参考。     

Multi-emissive 1D Cd(II) polymers with a biphenyl bridged bisazamacrocycle for ratiometric discrimination of nitroaromatics and selective visual detection of picric acid

Three one-dimensional ladder-like coordination polymers consisting of Cd₆ metalloring as the building unit, {[Cd₄LCl₄]·3H₂O}_n ( 1 ), {[Cd₃L(ClO₄)(H₂O)]ClO₄·3H₂O}_n ( 2 ), and {[Cd₆(L)₂(NO₃)₂(CH₃OH)(H₂O)](NO₃)₂·2CH₃OH·5H₂O}_n ( 3 ), were solvothermally constructed from a carboxylic functionalized bisazamacrocyclic ligand 4,4′-bis((4,7-bis(2-carboxyethyl)-1,4,7-triazacyclonon-1-yl)methyl)-1,1′-biphenyl (H₄L). These compounds dispersed in ethanol show the multiple emissions originating from the monomeric and intramolecularly overlapping biphenyl moieties which could be sensitively quenched by picric acid (PA) and 4-nitrophenol (4-NP) through the effective fluorescence resonance energy transfer process. The differential fluorescent responses of each compound on exposure to PA and 4-NP individually make the convenient ratiometric discrimination of two analytes based on the fluorescent intensity ratio (I₃₂₀/I₃₆₀) attainable, and 1 and 2 as ratiometric chemosensors for PA present a broad linear detection range from 4 to 300 μM with detection limits of 0.84 and 0.93 μM, respectively. Furthermore, the blue light emission of 1 under an ultraviolet lamp could be selectively quenched by PA even in the presence of all other interfering nitroaromatic pollutants, which empowers the fast visual detection of PA by naked eye.     

Nano-sized Cu(II) and Zn(II) complexes and their use as a precursor for synthesis of CuO and ZnO nanoparticles: A study on their sonochemical synthesis,characterization, and DNA-binding/cleavage,anticancer, and antimicrobial activities

Two new divalent copper (C1) and zinc (C2) chelates having the formulae [M(PIMC)₂] (where M = Cu(II), Zn(II) and PIMC = Ligand [(E)-3-(((3-hydroxypyridin-2-yl)imino)methyl)-4H-chromen-4-one] were obtained and characterized by several techniques. Structures and geometries of the synthesized complexes were judged based on the results of alternative analytical and spectral tools supporting the proposed formulae. IR spectral data confirmed the coordination of the ligands to the copper and zinc centers as monobasic tridentate in the enol form. Thermal analysis, UV-Vis spectra and magnetic moment confirmed the geometry around the copper center to be tetrahedral, square pyramidal and octahedral. Study of the binding ability of the synthesized compounds with Circulating tumor DNA (CT-DNA) bas been evaluated applying UV-Vis spectral titration and viscosity measurements. The copper and zinc oxides were achieved from the copper and zinc nano-particles structures Schiff base complexes as the raw material after calcination for 5 hr at 600°C. On the other hand, synthesized of C1 and C2 NPs were used as suitable precursors to the preparation of CuO and ZnO NPs. Finally, the synthesized of the two complexes exhibited enhanced activity against the tested bacterial (Staphylococcus aureus and Escherichia Coli) and fungal strains (Candida albicans and Aspergillus fumigatus) as compared to HPIMC. Among all these synthesized compounds, C1 exhibits good cleaving ability compared to other newly synthesized C2.     

Copper-based metal–organic framework decorated by CuO hair-like nanostructures: Electrocatalyst for oxygen evolution reaction

We report a Cu-based metal–organic framework (MOF) decorated by CuO nanostructures as an efficient catalyst for the oxygen evolution reaction (OER). MIL-53(Cu) was synthesized by a hydrothermal approach using 1,4-bezenedicarboxylic acid as organic precursor and further annealed at 300°C to form CuO nanostructures on its surface. The produced electrocatalyst, CuO@MIL-53(Cu), was characterized using various techniques. Under alkaline conditions, the developed electrocatalyst exhibited an overpotential of 801 and 336 mV versus RHE at 10 and 1 mA cm⁻², respectively. The reproducibility of the catalytic performance was validated using several electrodes. It was confirmed that the CuO hair-like nanostructures grown on MIL-53(Cu) using thermal treatment exhibit high OER activity, good kinetics and durability. CuO@MIL-53(Cu) is an economic noble-metal-free OER electrocatalyst. It has potential for application as anode material for sustainable energy technologies like batteries, fuel cells and water electrolysis.     

Biological Applications of Macrocyclic Schiff Base Ligands and Their Metal Complexes: A Survey of the Literature (2005–2019)

This article aims to provide a survey of biological applications of Schiff base macrocycles and their metal complexes, with emphasis given to the synthesis of the compounds and to their uses as antibacterial and antifungal agents. The literature on the subject, published during the 2005–2019 period, is shortly reviewed. This is an informed report collecting information on the addressed topic in a concise systematic way, and can be expected to be useful as a fast literature catalogue for researchers working on this and related domains.     

基于有序介孔碳的氯离子选择性电极的制备及其在手持传感系统中的应用

以有序介孔碳(OMC)球为离子-电子转换层,制备了固态氯离子选择性电极,构建了基于离子敏感的场效应晶体管(ISFET)的手持式传感系统,用于检测人体血清中的氯离子。优化了OMC前驱体的碳化温度,探究了OMC形貌结构对电极传感性能的影响;电极柔性化制备后考察了其在手持系统中对氯离子的检测效果。结果表明,最优条件下,电极在5.12×10^-4~1.02 mol/L的浓度范围呈现线性响应,响应斜率为60 mV/decade。该柔性电极在手持传感系统中展现出高灵敏度和重现性,可用于人体血清样品中氯离子的检测,其回收率为96.3%~104.9%。