Boosting the Activity of Pd Single Atoms by Tuning Their Local Environment on Ceria for Methane Combustion

Supported Pd single atom catalysts (SACs) have triggered great research interest in methane combustion yet with contradicting views on their activity and stability. Here, we show that the Pd SAs can take different electronic structure and atomic geometry on ceria support, resulting in different catalytic properties. By a simple thermal pretreatment to ceria prior to Pd deposition, a unique anchoring site is created. The Pd SA, taking this site, can be activated to Pd delta+ (0<2) that has greatly enhanced activity for methane oxidation: T-50 lowered by up to 130 degrees C and almost 10 times higher turnover frequency compared to the untreated catalyst. The enhanced activity of Pd delta+ site is related to its oxygen-deficient local structure and elongated interacting distance with ceria, leading to enhanced capability in delivering reactive oxygen species and decomposing reaction intermediates. This work provides insights into designing highly efficient Pd SACs for oxidation reactions.

Automated summary

In this study, different Pd single atom catalysts on ceria support were obtained by thermal pretreatment, leading to enhanced activity for methane oxidation. The enhanced activity is related to the oxygen-deficient local structure and elongated interacting distance with ceria.