Enhancing Methane Combustion Activity by Modulating the Local Environment of Pd Single Atoms in Pd<sub>1</sub>/CeO<sub>2</sub> Catalysts
Jinshu Tian, Ru Kong, Zhi Wang, Ling Fang, Tianyao He, Dong Jiang, Honggen Peng, Tulai Sun, Yihan Zhu, Yong Wang
Abstract
Reducing methane emissions is crucial for mitigating global warming. Developing highly efficient catalysts for low-temperature methane combustion is of great importance. Supported single-atom catalysts (SACs) have received significant attention in this regard. However, their long-term stability and activity remain challenging. In this study, we present a method for creating a highly active and thermally stable Pd 1 /CeO 2 catalyst by using thermal-shock synthesis (Pd 1 /CeO 2 -TS). By subjecting isolated Pd 2+ ions to ultrafast shockwaves, we control their local environment, resulting in unique electronic structures and the geometry of the Pd single atoms. Compared with the single-atom Pd 1 /CeO 2 catalyst formed through atom trapping (Pd 1 /CeO 2 -AT), Pd 1 /CeO 2 -TS showed improved activity for methane combustion with a nearly 20-fold increase in turnover frequency and reversible stability against water. This increase in activity is attributed to the presence of coordination-unsaturated Pd–O species and surface hydroxyls on ceria. These factors enhance the oxygen activity and reduce the barrier for C–H bond activation, resulting in increased catalytic performance.