Tan Linyan, Xiang Ganghua, Liu Zhigang
Advanced Catalytic Engineering Research Centre of the Ministry of Education, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, China.
Nanoscale. 2024 Mar 28;16(13):6720-6728. doi: 10.1039/d3nr06620g.
Noble metal catalysts exhibit high catalytic activity in lean CH combustion at low temperatures. However, the high surface energy of noble metal nanoparticles makes them susceptible to deactivation due to migratory-aggregation during the catalytic process. Herein, a core-shell structure with a Pd/CeO core and a SiO shell (denoted as Pd/CeO@SiO) was designed and prepared to enhance the thermal stability for catalytic lean CH combustion. A series of characterization methods demonstrated the successful encapsulation of SiO and the modified thermal stability. The results of activity tests indicated that Pd/CeO@SiO exhibited the optimal catalytic performance. After seven runs, Pd/CeO@SiO achieved 90% conversion of CH at 385 °C compared to Pd/CeO at 440 °C. The remarkable catalytic performance was attributed to the synergistic effect of strengthened metal-support interactions and the core-shell structure. On the one hand, the migration and aggregation of Pd nanoparticles were limited due to the protection of the SiO shell layer. On the other hand, the SiO shell layer further enhanced the interactions between the Pd nanoparticles and CeO, thus promoting the formation of PdCeO solid solutions and active oxygen species, which were beneficial for the improvement of the stability and redox capacity of the catalyst.
贵金属催化剂在低温贫燃CH燃烧中表现出高催化活性。然而,贵金属纳米颗粒的高表面能使其在催化过程中因迁移聚集而易于失活。在此,设计并制备了一种具有Pd/CeO核和SiO壳的核壳结构(表示为Pd/CeO@SiO),以提高催化贫燃CH燃烧的热稳定性。一系列表征方法证明了SiO的成功包覆以及热稳定性的改善。活性测试结果表明,Pd/CeO@SiO表现出最佳的催化性能。经过七次运行后,与在440°C的Pd/CeO相比,Pd/CeO@SiO在385°C时实现了90%的CH转化率。卓越的催化性能归因于强化的金属-载体相互作用和核壳结构的协同效应。一方面,由于SiO壳层的保护,Pd纳米颗粒的迁移和聚集受到限制。另一方面,SiO壳层进一步增强了Pd纳米颗粒与CeO之间的相互作用,从而促进了PdCeO固溶体和活性氧物种的形成,这有利于提高催化剂的稳定性和氧化还原能力。