Ga speciation and ethane dehydrogenation catalysis of Ga-CHA and MOR: Comparative investigation with Ga-MFI
Ga speciation and ethane dehydrogenation catalysis of Ga-CHA and MOR: Comparative investigation with Ga-MFI
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Ga-CHA 和 MOR 的 Ga 形态和乙烷脱氢催化：与 Ga-MFI 的比较研究
DOI：
10.1016/j.cattod.2022.06.039
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发表时间：
2023
期刊：
影响因子：
5.3
通讯作者：
Shimizu Ken-ichi
中科院分区：
文献类型：
--
作者：
Huang Mengwen;Maeno Zen;Toyao Takashi;Shimizu Ken-ichi
研究了Ga交换的CHA和MOR （Ga-CHA和Ga-MOR）分子筛的Ga形态和乙烷脱氢催化作用。这些结果与先前开发的高效Ga-MFI分子筛（Ga-MFI）进行了比较。在不同的负载条件（Ga/Al = 0.3, H2at = 550℃）和Ga/Al = 1.0, H2at = 800℃)下进行了还原固态离子交换（RSSIE）反应。利用红外光谱对CHA和MOR沸石中形成的分离的ga -氢化物进行了探测。通过nh3、吡啶（Py）吸附实验和x射线吸收光谱（XAS）表征了剩余Brønsted酸位（BASs）和其他分离Ga物种的形成。在非氧化乙烷脱氢过程中，高负荷Ga-MOR表现出高选择性和耐久性；然而，转化率低于高负荷Ga-MFI。在Ga-CHA的情况下，增加加载量并没有提高耐久性。通过动力学研究和H - D交换反应，探讨了Ga-MFI的催化性能优于Ga-CHA和MOR的原因。
This study investigated Ga speciation and ethane dehydrogenation catalysis of Ga-exchanged CHA and MOR (Ga-CHA and Ga-MOR) zeolites. These results were compared to the highly efficient Ga-exchanged MFI (Ga-MFI) zeolite previously developed. Reductive solid-state ion-exchange (RSSIE) reactions were conducted at varying loading conditions (Ga/Al = 0.3, H2at 550 °C and Ga/Al = 1.0, H2at 800 °C). Isolated Ga-hydrides formed in both CHA and MOR zeolites were probed using infrared (IR) spectroscopy. The remaining Brønsted acid sites (BASs) and formation of other isolated Ga species were characterized via NH3and pyridine (Py) adsorption experiments as well as X-ray absorption spectroscopy (XAS). In non-oxidative ethane dehydrogenation, high-loading Ga-MOR exhibited high selectivity and durability; however, the conversion was lower than high-loading Ga-MFI. In the case of Ga-CHA, increasing the loading amount did not improve the durability. The kinetic study and H−D exchange reactions were conducted to discuss the reason for better catalytic performance of Ga-MFI than those of Ga-CHA and MOR.