Li Boyu, Croiset Eric, Wen John Z
Department of Chemical Engineering, University of Waterloo, Waterloo, ON N2L3G1, Canada.
Department of Mechanical & Mechatronics Engineering, University of Waterloo, Waterloo, ON N2L3G1, Canada.
Nanomaterials (Basel). 2022 Jan 25;12(3):392. doi: 10.3390/nano12030392.
As the poor cycling stability of CeO catalysts has become the major obstacle for applications of diesel particulate filters (DPF), it is necessary to investigate how to reduce their structural and compositional changes during soot oxidation. In this study, different ratios of Samarium (Sm) were doped into the lattice of CeO nanoparticles to improve the catalytic performance as well as surface properties. The stability was investigated by recycling the catalyst, mixing it with soot again, and repeating the thermogravimetric analysis (TGA) tests seven times. Consistent observations were expected for more cycles. It was found that doping 5%, 10%, and 20% samarium into the CeO lattice can improve the catalyst stability but at the cost of losing some activity. While the catalyst became more stable with the increasing Sm doping, the 10% Sm-doped catalyst showed the best compromise between stability and activity. Ce and O were found to play important roles in controlling catalytic soot oxidation activity. These two species were directly related to oxygen vacancies and oxygen storage capacity of the catalyst. Sm-doped catalysts showed a minimized decrease in the Ce and O content when the fresh and spent catalysts were compared.
由于CeO催化剂较差的循环稳定性已成为柴油颗粒过滤器（DPF）应用的主要障碍，因此有必要研究如何减少其在碳烟氧化过程中的结构和组成变化。在本研究中，将不同比例的钐（Sm）掺杂到CeO纳米颗粒的晶格中，以提高催化性能和表面性质。通过循环使用催化剂、将其与碳烟再次混合并重复热重分析（TGA）测试七次来研究稳定性。预期更多循环会有一致的观察结果。结果发现，将5%、10%和20%的钐掺杂到CeO晶格中可以提高催化剂稳定性，但会损失一些活性。虽然随着Sm掺杂量的增加催化剂变得更稳定，但10% Sm掺杂的催化剂在稳定性和活性之间表现出最佳的平衡。发现Ce和O在控制催化碳烟氧化活性中起重要作用。这两种物质与催化剂的氧空位和储氧能力直接相关。当比较新鲜催化剂和使用过的催化剂时，Sm掺杂的催化剂显示出Ce和O含量的最小化降低。
