Xin Hui, Lin Le, Li Rongtan, Li Dan, Song Tongyuan, Mu Rentao, Fu Qiang, Bao Xinhe
State Key Laboratory of Catalysis, iChEM, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian 116023, P. R. China.
University of Chinese Academy of Sciences, Beijing 100049, China.
J Am Chem Soc. 2022 Mar 23;144(11):4874-4882. doi: 10.1021/jacs.1c12603. Epub 2022 Mar 8.
Encapsulation of metal nanoparticles by support-derived materials known as the classical strong metal-support interaction (SMSI) often happens upon thermal treatment of supported metal catalysts at high temperatures (≥500 °C) and consequently lowers the catalytic performance due to blockage of metal active sites. Here, we show that this SMSI state can be constructed in a Ru-MoO catalyst using CO hydrogenation reaction gas and at a low temperature of 250 °C, which favors the selective CO hydrogenation to CO. During the reaction, Ru nanoparticles facilitate reduction of MoO to generate active MoO overlayers with oxygen vacancies, which migrate onto Ru nanoparticles' surface and form the encapsulated structure, that is, Ru@MoO. The formed SMSI state changes 100% CH selectivity on fresh Ru particle surfaces to above 99.0% CO selectivity with excellent activity and long-term catalytic stability. The encapsulating oxide layers can be removed via O treatment, switching back completely to the methanation. This work suggests that the encapsulation of metal nanocatalysts can be dynamically generated in real reactions, which helps to gain the target products with high activity.
通过载体衍生材料对金属纳米颗粒进行封装，即所谓的经典强金属-载体相互作用（SMSI），通常在高温（≥500°C）下对负载型金属催化剂进行热处理时发生，由于金属活性位点被堵塞，从而降低了催化性能。在此，我们表明，这种SMSI状态可以在Ru-MoO催化剂中使用CO加氢反应气体并在250°C的低温下构建，这有利于将CO选择性加氢为CO。在反应过程中，Ru纳米颗粒促进MoO的还原，生成具有氧空位的活性MoO覆盖层，这些氧空位迁移到Ru纳米颗粒表面并形成封装结构，即Ru@MoO。形成的SMSI状态将新鲜Ru颗粒表面上100%的CH选择性转变为高于99.0%的CO选择性，同时具有优异的活性和长期催化稳定性。封装的氧化层可以通过O处理去除，完全恢复到甲烷化状态。这项工作表明，金属纳米催化剂的封装可以在实际反应中动态生成，这有助于以高活性获得目标产物。
