共查询到20条相似文献,搜索用时 31 毫秒
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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(35):10503-10508
Using quasi‐simultaneous in situ PXRD and XANES, the direct correlation between the oxidation state of Cu ions in the commercially relevant deNOx NH3‐SCR zeolite catalyst Cu‐CHA and the Cu ion migration in the zeolitic pores was revealed during catalytic activation experiments. A comparison with recent reports further reveals the high sensitivity of the redox‐active centers concerning heating rates, temperature, and gas environment during catalytic activation. Previously, Cu+ was confirmed present only in the 6R. Results verify a novel 8R monovalent Cu site, an eventually large Cu+ presence upon heating to high temperatures in oxidative conditions, and demonstrate the unique potential in combining in situ PXRD and XANES techniques, with which both oxidation state and structural location of the redox‐active centers in the zeolite framework could be tracked. 相似文献
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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(46):14650-14654
A viologen‐based Borromean entangled porous framework was found to be sensitive to both CuKα and MoKα X‐ray sources, showing rapid photochromic response and recovery within one minute. The X‐ray‐induced photochromic process is accompanied by a reversible single‐crystal‐to‐single‐crystal (SC‐SC) structural transformation, an unprecedented phenomenon for X‐ray sensitive materials. The complex can be further processed into portable thin films for detecting the dose of the X‐ray exposure. Moreover, the photochromism can occur over a broad temperature range of 100–333 K, both in the form of single crystals and thin films, making it a potential candidate for practical indoor and outdoor applications. 相似文献
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Chengyuan Wang Jing Zhang Guankui Long Naoki Aratani Hiroko Yamada Yang Zhao Qichun Zhang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2015,127(21):6390-6394
Increasing the length of N‐heteroacenes or their analogues is highly desirable because such materials could have great potential applications in organic electronics. In this report, the large π‐conjugated N‐heteroquinone 6,10,17,21‐tetra‐((triisopropylsilyl)ethynyl)‐5,7,9,11,16,18,20,22‐octaazanonacene‐8,19‐dione (OANQ) has been synthesized and characterized. The as‐prepared OANQ shows high stability under ambient conditions and has a particularly low LUMO level, which leads to it being a promising candidate for air‐stable n‐type field‐effect transistors (FETs). In fact, FET devices based on OANQ single crystals have been fabricated and an electron mobility of up to 0.2 cm2 V−1 s−1 under ambient conditions is reported. More importantly, no obvious degradation was observed even after one month. Theoretical calculations based on the single crystal are consistent with the measured mobility. 相似文献
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Alexander Hoffmann Stephan Binder Anton Jesser Roxana Haase Ulrich Flrke Manuel Gnida Marco SalomoneStagni Wolfram Meyer‐Klaucke Benjamin Lebsanft Lara Elena Grünig Simon Schneider Maryam Hashemi Arne Goos Alina Wetzel Michael Rübhausen Sonja Herres‐Pawlis 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(1):305-310
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Tatsuya Higaki Chong Liu David J. Morris Guiying He Tian‐Yi Luo Matthew Y. Sfeir Peng Zhang Nathaniel L. Rosi Rongchao Jin 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(52):18974-18978
The synthesis and structure of atomically precise Au130?xAgx (average x=98) alloy nanoclusters protected by 55 ligands of 4‐tert‐butylbenzenethiolate are reported. This large alloy structure has a decahedral M54 (M=Au/Ag) core. The Au atoms are localized in the truncated Marks decahedron. In the core, a drum of Ag‐rich sites is found, which is enclosed by a Marks decahedral cage of Au‐rich sites. The surface is exclusively Ag?SR; X‐ray absorption fine structure analysis supports the absence of Au?S bonds. The optical absorption spectrum shows a strong peak at 523 nm, seemingly a plasmon peak, but fs spectroscopic analysis indicates its non‐plasmon nature. The non‐metallicity of the Au130?xAgx nanocluster has set up a benchmark to study the transition to metallic state in the size evolution of bimetallic nanoclusters. The localized Au/Ag binary architecture in such a large alloy nanocluster provides atomic‐level insights into the Au?Ag bonds in bimetallic nanoclusters. 相似文献