Effects of Al distribution in the Cu-exchanged AEI zeolites on the reaction performance of continuous direct conversion of methane to methanol
Effects of Al distribution in the Cu-exchanged AEI zeolites on the reaction performance of continuous direct conversion of methane to methanol
复制标题
Cu交换AEI沸石中Al分布对甲烷连续直接转化制甲醇反应性能的影响
DOI：
10.1016/j.apcatb.2023.122395
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发表时间：
2023
期刊：
影响因子：
--
通讯作者：
Yokoi Toshiyuki
中科院分区：
文献类型：
--
作者：
Xiao Peipei;Wang Yong;Lu Yao;De Baerdemaeker Trees;Parvulescu Andrei-Nicolae;M?ller Ulrich;De Vos Dirk;Meng Xiangju;Xiao Feng-Shou;Zhang Weiping;Marler Bernd;Kolb Ute;Gies Hermann;Yokoi Toshiyuki
研究了有机结构导向剂（OSDA）对AEI分子筛骨架中Al原子的位置和含量、Cu的形态和酸性特征以及交换后的Cu/AEI分子筛催化剂在甲烷连续直接转化制甲醇（cDMTM）反应中的催化性能的影响。用Na阳离子合成的AEI沸石导致更多的Al和更高百分比的Al对比没有Na阳离子制备的沸石。结果表明，与不含Na阳离子的Cu/AEI分子筛催化剂相比，含Na阳离子的Cu/AEI分子筛催化剂具有较低的甲烷转化表观活化能和较高的甲醇生成速率，但由于含Na阳离子的Cu/AEI分子筛催化剂具有更高的双铜活性物种和更高的酸量，因此其在cDMTM反应中的稳定性较差.通过焙烧调整两种AEI分子筛骨架中相近的Al含量，以Na为阳离子合成的Cu/AEI分子筛表现出更高的甲醇选择性和更稳定的反应性能，这是由于Al的分布引起的Cu物种与酸中心之间的关系（如距离）不同。在350 °C的cDMTM反应中，甲醇生成速率为27.3 µmol·g−1·min− 1，选择性约为50%，性能稳定。此外，通过进一步焙烧以减少酸量，可提高5Cu/AEI分子筛催化剂的稳定性，使含Na阳离子的5Cu/AEI分子筛保持较高的甲醇生成速率，并获得新的反应稳定性。不含钠离子的5Cu/AEI分子筛，性能稳定，但甲醇生成率和选择性严重下降。本研究工作有助于开发具有不同Al分布的AEI沸石及其对Cu形态和酸性性质的显著影响，从而为获得用于从甲烷高效稳定地生产甲醇的稳健Cu/AEI沸石催化体系提供有价值的策略。
The effects of the organic structure-directing agent (OSDA) with or without Na cations for the synthesis of AEI zeolite on the location and content of the Al atoms in the framework as well as the Cu speciation and acidic features of the exchanged Cu/AEI zeolite catalysts and their catalytic properties in the continuous direct conversion of methane to methanol (cDMTM) were investigated. The AEI zeolite synthesized with Na cations led to more Al and a higher percentage of Al pairs than the one prepared without Na cations. Consequently, the Cu/AEI zeolite catalysts synthesized with Na cations exhibited lower apparent activation energy of methane conversion, higher methanol formation rate, and less stable ability in the cDMTM reaction due to the more active dicopper species and higher acid amount than those prepared without Na cations. Adjustment of the close Al content in the framework of the two AEI zeolites by calcination, the Cu/AEI zeolite synthesized with Na cations evidenced a higher methanol selectivity and more stable reaction performance because of the different relationship between Cu species and acid sites, such as the distance, caused by the Al distribution. The methanol formation rate of 27.3 µmol·g−1·min−1with about 50% selectivity and stable performance in the cDMTM reaction at 350 °C were obtained. Moreover, the stability of both 5Cu/AEI zeolite catalysts could be upgraded by further calcination to diminish the acid amount, the high methanol formation rate of the 5Cu/AEI zeolite synthesized with Na cations was maintained and the reaction stability was newly attained. The 5Cu/AEI zeolite synthesized without Na cations, merely the stable performance was reached, while the methanol formation rate and selectivity seriously declined. This work contributed to the development of AEI zeolite with different Al distributions and its significant impacts on the Cu speciation and acidic properties, thus providing a valuable strategy to obtain a robust Cu/AEI zeolite catalytic system for efficient and stable methanol production from methane.
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影响因子：
3.7
作者：
John M. Findley;P. Ravikovitch;D. Sholl
通讯作者：
John M. Findley;P. Ravikovitch;D. Sholl
影响因子：
12.9
作者：
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基于计算的吸附氮和一氧化碳的拉伸频率将振动光谱映射到沸石中铜物质的结构
DOI：
10.1021/acs.jpcc.1c01649
发表时间：
2021
期刊：
The Journal of Physical Chemistry C
影响因子：
--
作者：
D. Palagin;V. Sushkevich;Amy J. Knorpp;M. Ranocchiari;J. V. van Bokhoven
通讯作者：
J. V. van Bokhoven
影响因子：
12.9
作者：
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通讯作者：
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影响因子：
12.9
作者：
Knott, Brandon C.;Nimlos, Claire T.;Gounder, Rajamani
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Gounder, Rajamani