Single-Atom Ru on CeO2 Nanorods for Efficient N2O Decomposition: Mechanistic Insights and Multipollutant Control

Nitrous oxide (N2O) has gained increasing attention as a potent greenhouse gas, and its catalytic decomposition offers a promising mitigation strategy. In this study, single-atom Ru embedded in a rod-shaped CeO2 catalyst was synthesized via a H2O2 chemical etching strategy. The single-atom Ru catalyst demonstrated an exceptional N2O decomposition performance with only 0.48 wt % Ru loading, exhibiting a 34-fold increase in the turnover frequency compared to Ru nanoparticle catalysts. Under simulated exhaust conditions (NO, CO, and N2O), Ru1/CeO2 enabled complete conversion of all three pollutants at 280 °C. Mechanistic studies revealed that N2O decomposition over Ru1/CeO2 and Run/CeO2 followed the Mars–van Krevelen (MvK) and Langmuir–Hinshelwood (L–H) mechanisms, respectively. The exceptional N2O decomposition activity of the single-atom catalyst stems from enhanced O2 desorption through the recombination of oxygen atoms that dissociate from N2O with adjacent lattice oxygen. Notably, Ru1/CeO2 exhibits remarkable O2 tolerance due to the selective adsorption: N2O binds to single Ru atoms, whereas O2 occupies oxygen vacancies. In contrast, the high energy barrier associated with O2 combination and desorption in Run/CeO2 hindered N2O decomposition, and the competitive adsorption of O2 on its surface led to poor O2 resistance. This study demonstrates Ru1/CeO2 as an efficient catalyst for abating N2O and multipollutant removal.