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891.
892.
采用高稳定、高灵敏的纳米金/多孔二氧化硅复合材料作为SERS基底,构建了一种二维薄层色谱-表面增强拉曼散射(TLC-SERS)联用方法,该技术结合了薄层色谱(TLC)的快速分离功能和SERS定性定量分析的优点,提高了分离能力。采用对巯基苯胺作为探针分子研究了基底的均匀性和批-批重复性。Mapping扫描实验表明,24个测量点峰强度的相对标准偏差(RSD)为5.9%,说明该基底具有良好的点-点重复性。9个批次基底信号值的RSD为7.5%。将该基底用于糖精钠的检测,线性范围为0.1~200 mg/L,检出限为0.06 mg/L。用于实际样品测定,检测出饮料中糖精钠为141 mg/L,水果中为18 mg/L,10 min内能完成分析测试。该方法灵敏度高,特异性强,前处理方式简单,实现了饮料及水果中糖精钠的快速检测。 相似文献
893.
热分析联用技术是在热重分析基础上,将多种检测手段并用,准确地研究材料的结构、组成、热反应等特性,从而揭示材料热分解过程本质的技术。在程序升温过程中,利用热分析联用技术对金属材料的质量和热量变化及热分解产物成分等信息进行检测,能更精准地研究金属材料的组成和热分解特性。该文在热重分析法的基础上,着重介绍了其与差热分析、差示扫描量热分析、傅里叶红外光谱分析、质谱分析等分析方法的联用,并以金属材料研究为例,分析了热分析联用技术在金属材料的结构、性能测定等方面的应用,同时展望了热分析联用技术的应用前景。 相似文献
894.
895.
LI Yinyin WU Qiannan ZHANG Kai HU Bin LIN Yanhong WANG Dejun XIE Tengfeng 《高等学校化学研究》2020,36(6):1059-1067
Ti-Fe2O3 photoanode has received widespread attention in photoelectrochemical(PEC) water spilling because of its optimized oxidative and reductive capability of composites catalyst. However, its low efficiency could limit its development. Herein, in order to improve the efficiency of PEC water spilling, the all-solid-state direct Z-scheme Ti-ZnFe2O4/Ti-Fe2O3(TZFO/Ti-Fe2O3) nanorod arrays composited with the ideal energy band structure are synthesized by modulating the Fermi level of TZFO for PEC water splitting. The photophysical methods in this work, including the Kelvin probe measurement and transient photovoltage spectroscopy(TPV) measurement, are applied to explore the migration behavior of electric charges at the enhanced interface electric field. Finally, the Z-scheme charge transfer mechanism of TZFO/Ti-Fe2O3 photoanode is proved successfully. Benefiting from the desirable charge transfer at interface electric field, the TZFO/Ti-Fe2O3 exhibits the outstanding photocatalytic oxygen evolution reaction(OER) performance, and the photocurrent of 60TZFO/Ti-Fe2O3 photoanode reaches 2.16 mA/cm2 at 1.23 V vs. reversible hydrogen electrode(RHE), which is three times higher than that of pure Ti-Fe2O3 photoanode. This work provides a facile approach of modulating interface electric field to optimize the Z-scheme charge-transfer process. 相似文献
896.
A 1,10-phenanthroline based polymer named PPPhen(i.e., polymer from pyrene 1,10-phenanthrolin) was prepared by the Friedel-Crafts reaction of 1,10-phenanthroline and pyrene cross-linked with dimethoxymethane. The related Pd catalyst Pd@PPPhen was prepared by supporting Pd nanoparticles(NPs) on the PPPhen material. PPPhen and Pd@PPPhen were characterized by means of scanning electron microscopy(SEM), transmission electron microscopy, N2 adsorption-desorption, Fourier-transform infrared and X-ray photoelectron spectroscopy analyses. The results showed that PPPhen polymer was highly porous and that the phenanthroline group can enhance the stability of the Pd nanoparticles. Pd@PPPhen also exhibited good catalytic activity in the aerobic oxidation of alcohols to aldehydes and ketones, and Pd@PPPhen was recyclable with durable activity and retentive structures. 相似文献
897.
Dr. Baoyan Xing Dr. Sai Ge Prof. Jianguo Zhao Dr. Hui Yang Dr. Jie Song Dr. Yu Geng Dr. Yuying Qiao Prof. Ling Gu Prof. Peide Han Prof. Guibin Ma 《ChemistryOpen》2020,9(10):1018-1026
Solid-state NMR analysis on wurtzite alloyed CdSe1−xSx crystalline nanoparticles and nanobelts provides evidence that the 113Cd NMR chemical shift is not affected by the varying sizes of nanoparticles, but is sensitive to the S/Se anion molar ratios. A linear correlation is observed between 113Cd NMR chemical shifts and the sulfur component for the alloyed CdSe1−xSx (0<x<1) system both in nanoparticles and nanobelts (δCd=169.71⋅XS+529.21). Based on this correlation, a rapid and applied approach has been developed to determine the composition of the alloyed nanoscalar materials utilizing 113Cd NMR spectroscopy. The observed results from this system confirm that one can use 113Cd NMR spectroscopy not only to determine the composition but also the phase separation of nanomaterial semiconductors without destruction of the sample structures. In addition, some observed correlations are discussed in detail. 相似文献
898.
基于扫描电子显微镜的矿物自动分析仪(Quantitative Evaluation of Minerals by Scanning Electronic Microscopy)、MLA(Mineral Liberation Analyser)和AMICS(Advanced Mineral Identification and Characterization System)可用于测定选矿产品中目的矿物的粒度和单体解离度,为确定合理的磨矿细度以及优化选矿工艺流程提供依据。环氧树脂光片的制备是矿物自动识别和测量的最关键的一环,其代表性直接关系到后续数据测量的准确性和真实性。对于金属矿产品来说,由于选矿产品中矿物颗粒粗细不均、密度差异较大,在环氧树脂胶结固化过程中矿物颗粒会产生明显的分异作用并互相黏连,造成分析结果失真。实验证明,把样品与晶质石墨混均,然后加入环氧树脂以及固化剂搅拌混合倒入圆柱状模具进行冷镶嵌,待样品固化后再沿圆柱体的纵向进行切割,并对其切割面进行粗磨、细磨、精磨以及抛光,就可以制备出样品分散性好、分布均匀、表面光滑平整的具有代表性的环氧树脂光片。 相似文献
899.
900.
Covalent organic frameworks (COFs) as an emerging type of crystalline porous materials, have obtained considerable attention recently. They have exhibited diverse structure and attractive performance in various catalytic reactions. It is highly expected to have a systematic and comprehensive review summing up COFs‐derived catalysts in homogeneous and heterogeneous catalysis, which is favorable to the judicious design of an efficient catalyst for targeted reaction. Herein, we focus on summarizing recent and significant developments in COFs materials, with an emphasis on both the synthetic strategies and targeted functionalization, and categorize it in accordance with the different types of catalytic reactions. Their potential catalysis applications are reviewed thoroughly. Moreover, a personal view about the future development of COFs catalysts with respect to the large‐scale production is also discussed. 相似文献