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 Brønsted acid sites were the active sites in Ag/zeolites; the deactivated Ag/zeolites had no available Brønsted acid sites. When the number of Brønsted 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 Brønsted acid sites led to the disappearance of available Brønsted acid sites and thus resulted in Ag/zeolite catalyst deactivation. An understanding of the active sites and deactivation mechanism in ethylene oxidation on zeolite catalysts is helpful in the synthesis of a better ethylene oxidation catalyst and development of an effective technology of eliminating trace ethylene.

中文翻译：

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了解Ag /沸石的活性位点和室温下乙烯催化氧化的失活机理

发现微孔银/沸石（ZSM-5，β，Y和丝光沸石）催化剂是室温下乙烯氧化的潜在良好催化材料。在干燥和潮湿的气氛下对这些催化剂进行了评估，在25°C下实现了100 ppm的乙烯矿化成CO _2的100％转化。而且，沸石骨架类型和相对湿度对催化稳定性有显着影响。吡啶傅里叶变换红外光谱（FTIR）和固态氢-1（¹H）魔角旋转核磁共振（MAS NMR）研究表明，布朗斯台德酸位点是Ag /沸石中的活性位点；失活的Ag /沸石没有可用的布朗斯台德酸位。当减少Ag / ZSM-5-湿润和Ag / Beta湿润的布朗斯台德酸中心数目时，Ag / ZSM-5-湿润和Ag / Beta湿润的催化活性降低。程序升温氧化质谱（TPO-MS）和水吸附/解吸结果表明H ₂吸附在布朗斯台德酸性位点上的O导致可用的布朗斯台德酸性位点消失，从而导致Ag /沸石催化剂失活。了解沸石催化剂上乙烯氧化的活性位和失活机理，有助于合成更好的乙烯氧化催化剂和开发消除痕量乙烯的有效技术。