Wang Yansu, Suo Yujun, Ren Jin-Tao, Wang Zheng, Yuan Zhong-Yong
Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), School of Materials Science and Engineering, Nankai University, Tianjin 300350, China.
State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering, Ningxia University, Yinchuan 750021, Ningxia, China.
J Colloid Interface Sci. 2021 Jul 15;594:113-121. doi: 10.1016/j.jcis.2021.03.023. Epub 2021 Mar 10.
The "active site isolation" strategy has been proved to be efficient for enhancing the catalytic performance in propane dehydrogenation (PDH). Herein, spatially isolated cobalt oxide sites within nitrogen-doped carbon (NC) layers supported on silicalite-1 zeolite (CoO@NC/S-1) were synthesized by a two-step process consisting of the pyrolysis of bimetallic Zn/Co zeolitic imidazole frameworks loaded on silicalite-1 (ZnCo-ZIF/S-1) under N and the subsequent calcination in air atmosphere. This catalyst possesses exceptional catalytic performance for PDH with the propane conversion of 40% and the propene selectivity of >97%, and no apparent deactivation is observed after 10 h PDH reaction at 600 °C. With intensive characterizations and experiments, it is indicated that the real active sites of CoO@NC/S-1 are isolated CoO sites during the PDH process. In situ FT-IR spectroscopy shows the same intermediate product (Co-CH) during both propane dehydrogenation and propene hydrogenation, indicating that they have a reverse reaction process, and a reaction mechanism for PDH is proposed accordingly.
“活性位点隔离”策略已被证明在提高丙烷脱氢（PDH）的催化性能方面是有效的。在此，通过两步法合成了负载在硅沸石-1（CoO@NC/S-1）上的氮掺杂碳（NC）层内空间隔离的氧化钴位点，该两步法包括在氮气下热解负载在硅沸石-1上的双金属锌/钴沸石咪唑框架（ZnCo-ZIF/S-1）以及随后在空气气氛中煅烧。该催化剂对PDH具有优异的催化性能，丙烷转化率为40%，丙烯选择性>97%，在600℃下进行10小时PDH反应后未观察到明显失活。通过深入的表征和实验表明，CoO@NC/S-1在PDH过程中的实际活性位点是隔离的CoO位点。原位傅里叶变换红外光谱显示，在丙烷脱氢和丙烯加氢过程中都有相同的中间产物（Co-CH）出现，表明它们存在逆反应过程，并据此提出了PDH的反应机理。
