Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, 310027, Hangzhou, China.
Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering and College of Engineering, Peking University, 100871, Beijing, China.
Nat Commun. 2023 Mar 17;14(1):1478. doi: 10.1038/s41467-023-37261-x.
Oxidative dehydrogenation of propane is a promising technology for the preparation of propene. Boron-based nonmetal catalysts exhibit remarkable selectivity toward propene and limit the generation of CO byproducts due to unique radical-mediated C-H activation. However, due to the high barrier of O-H bond cleavage in the presence of O, the radical initialization of the B-based materials requires a high temperature to proceed, which decreases the thermodynamic advantages of the oxidative dehydrogenation reaction. Here, we report that the boron oxide overlayer formed in situ over metallic Ni nanoparticles exhibits extraordinarily low-temperature activity and selectivity for the ODHP reaction. With the assistance of subsurface Ni, the surface specific activity of the BO overlayer reaches 93 times higher than that of bare boron nitride. A mechanistic study reveals that the strong affinity of the subsurface Ni to the oxygen atoms reduces the barrier of radical initiation and thereby balances the rates of the BO-H cleavage and the regeneration of boron hydroxyl groups, accounting for the excellent low-temperature performance of Ni@BO/BN catalysts.
丙烷的氧化脱氢是制备丙烯的一种很有前途的技术。基于硼的非金属催化剂对丙烯具有显著的选择性，并由于独特的自由基介导的 C-H 活化作用限制了 CO 副产物的生成。然而，由于在 O 存在的情况下 O-H 键的断裂势垒较高，B 基材料的自由基引发需要较高的温度才能进行，这降低了氧化脱氢反应的热力学优势。在这里，我们报告了在金属 Ni 纳米粒子上原位形成的氧化硼覆盖层在 ODHP 反应中表现出异常低温的活性和选择性。在亚表面 Ni 的辅助下，BO 覆盖层的表面比表面积活性比裸露的氮化硼高 93 倍。一项机理研究表明，亚表面 Ni 对氧原子的强亲和力降低了自由基引发的势垒，从而平衡了 BO-H 断裂和硼羟基基团再生的速率，这解释了 Ni@BO/BN 催化剂在低温下的优异性能。
Zotero 插件