Electrodes surface-intercalated with powder catalysts: II. Microelectrodes surface-intercalated with powder catalysts

Microelectrode techniques were worked out for the study of electrocatalytic behaviors of powder catalysts. Ultra thin layer of fine catalyst powder was intercalated into the surface layer of soft conductive plastic sheet made from acetylene black and polytetrafluoroethylene (PTFE) binder. Microelectrodes of such construction have been successfully employed in the study of reversible and irreversible electrode reactions. Experimental results clearly indicated that microelectrode with ultra thin layer of surface-intercalated catalyst powder could serve as a powerful tool for the study of electrocatalytic behaviors of powder catalysts.     

NIR-II Fluorescent Brightness Promoted by “Ring Fusion” for the Detection of Intestinal Inflammation

Fluorophores with emission in the second near-infrared window (NIR-II) have displayed salient advantages for biomedical applications. However, the common strategy of reducing the energy bandgap of fluorophores so as to achieve red-shifted wavelengths always leads to compromised fluorescent brightness. Herein, we propose a molecular design concept of “ring-fusion” to modify the acceptor of AIEgen that can extend the luminous wavelength from NIR-I to NIR-II. The fused-acceptor-containing fluorophore yielded, TTQP, has an enhanced absorption coefficient with a higher brightness in nanoparticle formation compared to its NIR-I emissive counterpart (TTQ-DP) with a non-fused acceptor. Theoretical calculation further confirms that the ring fusion can efficiently promote the rigidity and planarity of the electron-deficient core, leading to a lower reorganization energy and nonradiative decay. The TTQP NPs yielded thus allow sensitive NIR-II fluorescence imaging of vasculature and intestinal inflammation in mice models. Therefore, we anticipate that our work will provide a promising molecular-engineering strategy to enrich the library and broaden the application scope of NIR-II fluorophores.     

硫酸水溶液中铅阳极膜形成及其结构的非现场FTIR反射吸收光谱—电化学研究

本文用非现场红外反射吸收光谱方法和电化学循环伏安法研究了1.0mol·dm~(-3)H_2SO_4中-0.6至2.5伏电势范围内(相对SCE)Pb阳极膜的形成及其可能的结构。在此电势区内Pb阳极膜中始终存在硫酸铅或碱式硫酸铅,其中SO_4~(2-)主要以桥式双齿配位方式与Pb~(2+)结合。另外,上述电势范围内生成的膜中无可检测量的H_2O和OH~-存在。     

溶剂工程调控钙钛矿薄膜中PbI2和PbI2(DMSO)的形成

钙钛矿太阳能电池以其高效、低成本的特点备受关注。到目前为止,钙钛矿太阳能电池的最高光电转换效率已经超过25%,显示出良好的应用前景。钙钛矿薄膜的结晶性能是决定器件性能的关键,因此,调控钙钛矿薄膜的生长过程至关重要。本工作中,我们发现通过简单调节前驱体溶剂,即调节二甲基亚砜：1, 4-丁内酯: N, N-二甲基甲酰胺(DMSO : GBL : DMF)的三种混合溶剂的比例,可实现钙钛矿薄膜中PbI₂和PbI₂(DMSO)含量的调节,从而调节电池的器件性能。此外,本工作系统研究了PbI₂和PbI₂(DMSO)的含量对器件性能的影响。结果表明,PbI₂(DMSO)的形成会导致300–425 nm波长范围内电池的外量子效率(EQE)降低,从而导致器件性能下降。相反,通过在前驱体溶液中添加额外的碘化亚甲基铵(MAI),可以抑制PbI₂和PbI₂(DMSO)的形成。     

从纸上到躬行:基于有机化学理论和文献的实验设计及优化之低年级本科教学初探

国际公认化学类本科生的培养目标是能够胜任化学专业技术职务,或具备相关的科研能力,而核心考核因素之一被认为是能否以纸上所学理论和文献助力实验方案的设计,并躬行实现。我们在有机化学基础实验教学中融合以上理念,初步探索出适合低年级本科生的以理论知识和文献指导实验设计和优化的教学策略。以乙酰二茂铁的合成为例,以问题-讨论为主线,引导学生从文献、底物的电子结构、傅-克酰基化反应机理和重要的物理化学性质等进行综合分析,设计乙酰二茂铁的合成路线,鼓励学生对教材提出质疑并自主设计和开展验证实验,对教材中的经典方法持续优化。学生深度参与实验路线设计和关键参数设置,沉浸学术研究氛围,敢于质疑并验证,提升了将已学理论转化为解决实际问题的能力,一定程度上有利于其科学思维和科研执行力的培养,提高其从事化学专业技术职务或相关科研工作的核心竞争力。     

Controllable Photoelectric Properties of Carbon Dots and Their Application in Organic Solar Cells

Organic solar cells are a current research hotspot in the energy field because of their advantages of lightness,translucency,roll to roll printing and building integration.With the rapid development of small molecule acceptor materials with high-performance,the efficiency of organic solar cells has been greatly improved.Further improving the device efficiency and stability and reducing the cost of active layer materials will contribute to the industrial development of organic solar cells.As a novel type of carbon nanomaterials,carbon dots gradually show great application potential in the field of organic solar cells due to their advantages of low preparation cost,non-toxicity and excellent photoelectric performance.Firstly,the synthesis and classification of carbon dots are briefly introduced.Secondly,the photoelectric properties of carbon dots and their adjusting,including adjustable surface energy level structure,good film-forming performance and up/down conversion characteristics are summarized.Thirdly,based on these intrinsic properties,the feasibility and advantages of carbon dots used in organic solar cells are discussed.Fourthly,the application progress of carbon dots in the active layer,hole transport layer,electron transport layer,interface modification layer and down-conversion materials of organic solar cells is also reviewed.Finally,the application progress of carbon dots in organic solar cells is prospected.Several further research directions,including in-depth exploration of the controllable preparation of carbon dots and their application in the fields of interface layer and up/down conversion for improving efficiency and stability of device are pointed out.     

Theoretical study on the reaction mechanism and thermodynamics of tin oxidation by oxygen species and chlorine species

In this work ab initio molecular orbital methods were employed to study the coal combustion reaction mechanisms of tin oxidized by different oxidants, including HOCl, HCl, ClO, ClO₂, NO₃, CO₂, and O₂. Eleven reaction pathways were identified. The results show that Sn can react with HCl, ClOO, CO₂, O₂, and NO₃ to form SnO and SnCl. SnO can be oxidized into SnCl by HOCl and HCl. SnCl can be further oxidized into a soluble compound, SnCl₂. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005     

有机化学基础实验课程一流建设

Green chemistry oriented instrument platform on preparation, purification and characterization for basic organic chemistry experiment course is constructed, and basic, comprehensive and innovative experimental projects were implemented to build a green, hierarchical and informationized curriculum system. Using information technology, new media and the Internet as the means and adopting various teaching modes, online and offline teaching of basic experiment of organic chemistry are carried out to benefit teacher-student interaction, flipped classroom, teaching and learning. The curriculum content reform is led by teaching and scientific research achievements, emphasizing the integration of theory and practice, the integration of tradition and frontier, increasing the interest and frontier of the curriculum, so as to realize the high-level, innovative and challenging nature of the curriculum.     

The Functionality of Surface Hydroxy Groups on the Selectivity and Activity of Carbon Dioxide Reduction over Cuprous Oxide in Aqueous Solutions

Carbon dioxide (CO₂) reduction in aqueous solutions is an attractive strategy for carbon capture and utilization. Cuprous oxide (Cu₂O) is a promising catalyst for CO₂ reduction as it can convert CO₂ into valuable hydrocarbons and suppress the side hydrogen evolution reaction (HER). However, the nature of the active sites in Cu₂O remains under debate because of the complex surface structure of Cu₂O under reducing conditions, leading to limited guidance in designing improved Cu₂O catalysts. This paper describes the functionality of surface‐bonded hydroxy groups on partially reduced Cu₂O(111) for the CO₂ reduction reaction (CO₂RR) by combined density functional theory (DFT) calculations and experimental studies. We find that the surface hydroxy groups play a crucial role in the CO₂RR and HER, and a moderate coverage of hydroxy groups is optimal for promotion of the CO₂RR and suppression of the HER simultaneously. Electronic structure analysis indicates that the charge transfer from hydroxy groups to coordination‐unsaturated Cu (Cu_CUS) sites stabilizes surface‐adsorbed COOH*, which is a key intermediate during the CO₂RR. Moreover, the CO₂RR was evaluated over Cu₂O octahedral catalysts with {111} facets and different surface coverages of hydroxy groups, which demonstrates that Cu₂O octahedra with moderate coverage of hydroxy groups can indeed enhance the CO₂RR and suppress the HER.     

LC-ESI-MS Determination of Roxithromycin in Tissues of Beagle Dogs after Multiple Dosing of Roxithromycin Sustained Release Tablets

Roxithromycin, often regarded as an ‘advanced-generation’ macrolide, is widely used throughout the world. To exactly evaluate the efficacy of roxithromycin sustained release tablets on tissue pharmacokinetic and pharmacodynamic parameters, we developed a reliable LC-ESI-MS method for the determination of roxithromycin in beagle dog tissues. The overall chromatographic run time was 3.2 min. This method involved the homogenization of tissues followed by an economical liquid-liquid extraction in 2.0 mL Eppendorf tubes. Selected ion monitoring (SIM) in positive mode was used for the quantification of roxithromycin at m/z 837.45 and clarithromycin (internal standard) at m/z 748.45. The method was validated to be accurate, precise and rugged with good linearity in all tissue homogenates. The method has been successfully applied to determine roxithromycin in many dog tissues and has been used for tissue distribution of roxithromycin studies. The present study demonstrates that the highest tissue concentration of roxithromycin was observed in the liver, followed by lung, spleen, kidney and heart after multiple dosing of sustained release tablets.