King Abdullah University of Science and Technology (KAUST), KAUST Catalysis Center (KCC), Physical Sciences and Engineering Division (PSE), 4700 KAUST, Thuwal, 23955-6900, Saudi Arabia.
Department of Chemical and Petroleum Engineering, Department of Chemistry, University of Kansas, Lawrence, KS, 66045, USA.
Angew Chem Int Ed Engl. 2017 Aug 21;56(35):10403-10407. doi: 10.1002/anie.201704758. Epub 2017 Jul 24.
Sodium-based catalysts (such as Na WO ) were proposed to selectively catalyze OH radical formation from H O and O at high temperatures. This reaction may proceed on molten salt state surfaces owing to the lower melting point of the used Na salts compared to the reaction temperature. This study provides direct evidence of the molten salt state of Na WO , which can form OH radicals, using in situ techniques including X-ray diffraction (XRD), scanning transmission electron microscopy (STEM), laser induced fluorescence (LIF) spectrometry, and ambient-pressure X-ray photoelectron spectroscopy (AP-XPS). As a result, Na O species, which were hypothesized to be responsible for the formation of OH radicals, have been identified on the outer surfaces at temperatures of ≥800 °C, and these species are useful for various gas-phase hydrocarbon reactions, including the selective transformation of methane to ethane.
钠离子催化剂（如 NaWO）被提议用于在高温下选择性地催化 H2O 和 O2 生成 OH 自由基。由于所用 Na 盐的熔点低于反应温度，因此该反应可能在熔融盐状态表面上进行。本研究使用包括 X 射线衍射（XRD）、扫描透射电子显微镜（STEM）、激光诱导荧光（LIF）光谱和常压 X 射线光电子能谱（AP-XPS）在内的原位技术，为 NaWO 的熔融盐状态提供了直接证据，该物质可以形成 OH 自由基。结果表明，在≥800°C 的温度下，在表面上形成了 NaO 物种，这些物种对于各种气相烃类反应（包括甲烷选择性转化为乙烷）非常有用。
