Single-Atom Ru on CeO 2 Nanorods for Efficient N 2 O Decomposition: Mechanistic Insights and Multipollutant Control

Nitrous oxide (N 2 O) 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 CeO 2 catalyst was synthesized via a H 2 O 2 chemical etching strategy. The single-atom Ru catalyst demonstrated an exceptional N 2 O 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 N 2 O), Ru 1 /CeO 2 enabled complete conversion of all three pollutants at 280 °C. Mechanistic studies revealed that N 2 O decomposition over Ru 1 /CeO 2 and Ru n /CeO 2 followed the Mars–van Krevelen (MvK) and Langmuir–Hinshelwood (L–H) mechanisms, respectively. The exceptional N 2 O decomposition activity of the single-atom catalyst stems from enhanced O 2 desorption through the recombination of oxygen atoms that dissociate from N 2 O with adjacent lattice oxygen. Notably, Ru 1 /CeO 2 exhibits remarkable O 2 tolerance due to the selective adsorption: N 2 O binds to single Ru atoms, whereas O 2 occupies oxygen vacancies. In contrast, the high energy barrier associated with O 2 combination and desorption in Ru n /CeO 2 hindered N 2 O decomposition, and the competitive adsorption of O 2 on its surface led to poor O 2 resistance. This study demonstrates Ru 1 /CeO 2 as an efficient catalyst for abating N 2 O and multipollutant removal.