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ZnO Nanoparticles Encapsulated in Nitrogen-Doped Carbon Material and Silicalite-1 Composites for Efficient Propane Dehydrogenation

2019, Zhao, Dan, Li, Yuming, Han, Shanlei, Zhang, Yaoyuan, Jiang, Guiyuan, Wang, Yajun, Guo, Ke, Zhao, Zhen, Xu, Chunming, Li, Ranjia, Yu, Changchun, Zhang, Jian, Ge, Binghui, Kondratenko, Evgenii V.

Chemistry; Catalysis; Nanoparticles © 2019 The Author(s)Non-oxidative propane dehydrogenation (PDH)is an attractive reaction from both an industrial and a scientific viewpoint because it allows direct large-scale production of propene and fundamental analysis of C-H activation respectively. The main challenges are related to achieving high activity, selectivity, and on-stream stability of environment-friendly and cost-efficient catalysts without non-noble metals. Here, we describe an approach for the preparation of supported ultrasmall ZnO nanoparticles (2–4 nm, ZnO NPs)for high-temperature applications. The approach consists of encapsulation of NPs into a nitrogen-doped carbon (NC)layer in situ grown from zeolitic imidazolate framework-8 on a Silicalite-1 support. The NC layer was established to control the size of ZnO NPs and to hinder their loss to a large extent at high temperatures. The designed catalysts exhibited high activity, selectivity, and on-stream stability in PDH. Propene selectivity of about 90% at 44.4% propane conversion was achieved at 600°C after nearly 6 h on stream. © 2019 The Author(s)

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Peculiarities of electronic structure and composition in ultrasound milled silicon nanowires

2020, Parinova, E.V., Pisliaruk, A.K., Schleusener, A., Koyuda, D.A., Chumakov, R.G., Lebedev, A.M., Ovsyannikov, R., Makarova, A., Smirnov, D., Sivakov, V., Turishchev, S.Yu.

The combined X-ray absorption and emission spectroscopy approach was applied for the detailed electronic structure and composition studies of silicon nanoparticles produced by the ultrasound milling of heavily and lowly doped Si nanowires formed by metal-assisted wet chemical etching. The ultrasoft X-ray emission spectroscopy and synchrotron based X-ray absorption near edges structure spectroscopy techniques were utilize to study the valence and conduction bands electronic structure together with developed surface phase composition qualitative analysis. Our achieved results based on the implemented surface sensitive techniques strongly suggest that nanoparticles under studies show a significant presence of the silicon suboxides depending on the pre-nature of initial Si wafers. The controlled variation of the Si nanoparticles surface composition and electronic structure, including band gap engineering, can open a new prospective for a wide range Si-based nanostructures application including the integration of such structures with organic or biological systems. © 2020

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Propagating and localized surface plasmon resonance sensing — A critical comparison based on measurements and theory

2016, Jatschka, Jacqueline, Dathe, André, Csáki, Andrea, Fritzsche, Wolfgang, Stranik, Ondrej

With its potential for ultrasensitive, label-free detection of molecular interactions, sensing methods based on the surface plasmon resonance (SPR) effect fully meet the requirements for modern analytical techniques. Already established by using propagating SPR in thin gold layers, the last years witnessed the emergence of another related technique utilizing extremely miniaturized noble metal sensor structures, based on a localized SPR. This paper provides a critical comparison of these kinds of SPR sensing, reviews the foundation of both general approaches, presents experimental data on exactly the same molecular model system using both techniques, as well as theoretical considerations in order to allow reasonable comparison. It highlights the specific features and effects, in order to provide guidance in choosing the right technique for given bioanalytical tasks. The study demonstrated the capabilities of LSPR for sensing of molecular layers even in the lower nanometer dimension. For the detection of small (bio)molecules, smaller particle diameters are favored regarding highest sensitivity. It also presents an approach to obtain refractive index and the thickness of a molecular film by analyzing the signal response of plasmonic sensors with metal nanoparticles. Moreover, an additional method for the improvement of the parameters' determination is introduced.