Regeneration of La<sub>2</sub>O<sub>3</sub>-Supported Pt Nanoparticles Giving High Loadings of Thermally Stable Pt Single Atoms on La<sub>2</sub>O<sub>3</sub> Supports: Implications for Catalysis
Yanxia Gao, Dongxu Yan, Chunqi Wang, Jing Chen, Jin Chen, Hongpeng Jia
Abstract
Improving the loading content and stability of a noble metal for single-atom catalysts (SACs) is extremely important for its industrial catalytic applications, but there are still formidable challenges, especially on metal oxide-supported SACs for a high-temperature catalytic reaction, such as CH4 oxidation. Herein, we utilize carbon escaping during La2O3 regeneration from La2O2CO3 to immediately capture and confine PtO2 species released from Pt nanoparticles (NPs) and obtain high-loading Pt single atoms on La2O3, which are extremely stable even after calcination at 800 °C for 5 days in air. Moreover, the atomization of Pt NPs and stabilization of Pt atoms can also be fulfilled during the in situ high-temperature reaction process effectively improving catalytic oxidation activity of CH4. The obtained SACs can serve as a single-atom active component precursor for loading on the surface of metal oxides such as ceria, which can significantly improve CH4 oxidation performance with a low Pt content. After achieving the Pt SAC loading, CH4 conversions on commercial CeO2 and CeO2 prepared using the precipitation method are increased by 40 and 70% at 700 °C, respectively. This facile and economic strategy simplifies the controllable preparation of thermally stable SACs and further broadens the practical application of SACs under various conditions.