Fan Weidong, Liu Dongyuan, Wang Xia, Liu Xiuping, Cao Dongwei, Fan Lili, Huang Zhaodi, Guo Wenyue, Sun Daofeng
School of Materials Science and Engineering, College of Science, China University of Petroleum (East China) Qingdao Shandong 266580 China
College of Materials Science and Engineering, Linyi University Linyi Shandong 276000 China.
Nanoscale Adv. 2019 Dec 31;2(2):755-762. doi: 10.1039/c9na00744j. eCollection 2020 Feb 18.
A new Pd/Ce based metal-organic framework is designed and synthesized as a self-sacrificial template for fabrication of an efficient catalyst for CO oxidation. The catalyst obtained by thermal annealing at 700 °C (Pd/CeO@NC-700) is composed of N-doped carbon with embedded Pd and CeO nanoparticles, which are highly dispersed and closely connected in the N-doped carbon; the high Pd loading (33.7 wt%) and the coupling between Pd and the CeO phase synergistically boost the CO oxidation performance. The Pd/CeO@NC-700 catalyst exhibits a 100% conversion temperature of 89 °C and excellent long-term stability. By combining structural characterization with density functional theory calculations, two possible CO oxidation pathways of TPB and TOP are revealed, in which the adsorbed O directly dissociates to O* atoms and activates CO* molecules. The transfer of O* between Pd and Ce (TPB) or Pd and Pd (TOP) facilitates the formation of intermediates and finally results in the production of CO. This work provides a new insight into the development of novel efficient catalysts for CO oxidation based on metal-organic frameworks.
设计并合成了一种新型的基于钯/铈的金属有机框架，作为制备用于一氧化碳氧化的高效催化剂的自牺牲模板。通过在700℃热退火得到的催化剂（Pd/CeO@NC-700）由嵌入钯和氧化铈纳米颗粒的氮掺杂碳组成，这些纳米颗粒在氮掺杂碳中高度分散且紧密相连；高钯负载量（33.7 wt%）以及钯与氧化铈相之间的耦合协同提高了一氧化碳氧化性能。Pd/CeO@NC-700催化剂的100%转化温度为89℃，并具有出色的长期稳定性。通过将结构表征与密度泛函理论计算相结合，揭示了两种可能的一氧化碳氧化途径，即边位（TPB）和顶位（TOP）途径，其中吸附的氧直接解离为O原子并激活CO分子。O*在钯和铈之间（TPB）或钯和钯之间（TOP）的转移促进了中间体的形成，最终导致一氧化碳的生成。这项工作为基于金属有机框架开发新型高效一氧化碳氧化催化剂提供了新的见解。
