Understanding the Active Sites of Ag/Zeolites and Deactivation Mechanism of Ethylene Catalytic Oxidation at Room Temperature
Understanding the Active Sites of Ag/Zeolites and Deactivation Mechanism of Ethylene Catalytic Oxidation at Room Temperature
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了解银/沸石的活性位点和乙烯室温催化氧化失活机制
DOI：
10.1021/acscatal.7b02410
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发表时间：
2018-02-01
期刊：
影响因子：
12.9
通讯作者：
Hao, Zhengping
中科院分区：
文献类型：
--
作者：
Yang, Hongling;Ma, Chunyan;Hao, Zhengping
微孔Ag/沸石（ZSM-5、Beta、Y和丝光沸石）催化剂被发现是室温下乙烯氧化的潜在良好催化材料。这些催化剂在干燥和潮湿气氛下进行评价，在25 °C下实现了100 ppm矿化为CO2的乙烯的100%转化率。此外，沸石骨架类型和相对湿度对催化剂稳定性有显著影响。吡啶傅里叶变换红外光谱（FTIR）和固态氢-1（1H）魔角自旋核磁共振（MAS NMR）研究表明，Ag/沸石中的活性中心为Bronsted酸中心，失活的Ag/沸石中没有Bronsted酸中心。当Ag/ZSM-5-humid和Ag/Beta-humid的B酸中心数减少时，催化活性降低。程序升温氧化质谱（TPO-MS）和水吸附/脱附结果表明，H2O吸附在Bronsted酸中心上。
Microporous Ag/zeolite (ZSM-5, Beta, Y, and Mordenite) catalysts were found to be potentially good catalytic materials for ethylene oxidation at room temperature. These catalysts were evaluated under both dry and humid atmospheres, achieving 100% conversion of 100 ppm of ethylene mineralized into CO2 at 25 °C. Moreover, the zeolite framework type and relative humidity had a significant effect on catalytic stability. Pyridine Fourier transform infrared spectra (FTIR) and solid-state hydrogen-1 (1H) magic angle spinning nuclear magnetic resonance (MAS NMR) studies revealed that Bronsted acid sites were the active sites in Ag/zeolites; the deactivated Ag/zeolites had no available Bronsted acid sites. When the number of Bronsted acid sites of Ag/ZSM-5-humid and Ag/Beta-humid were reduced, the catalytic activities of Ag/ZSM-5-humid and Ag/Beta-humid decreased. Temperature-programmed oxidation mass spectrometry (TPO-MS) and water adsorption/desorption results indicated that H2O adsorbed on Bronsted acid sites l...