CaO-Doped Rh/Al2O3 as a Highly Effective Catalyst for Catalytic N2O Decomposition
The direct catalytic decomposition of the greenhouse gas N2O into nitrogen and oxygen holds significant environmental importance. In this study, CaO-modified Rh-based catalysts were prepared via a stepwise impregnation method. The catalyst structures were characterized, and their catalytic performances for N2O decomposition were investigated. The characterization results demonstrate that CaO doping significantly enhances catalytic activity and water resistance. Specifically, the 0.5Rh/Al2O3 catalyst exhibited a N2O conversion below 5% at 300 °C, whereas the 0.5Rh-4Ca/Al2O3 catalyst achieved 50% conversion under identical conditions, indicating markedly improved low-temperature activity. Compared to the undoped catalyst (0.5Rh/Al2O3), CaO doping (0.5Rh-xCa/Al2O3) strengthens metal-support interactions, improves Rh dispersion on the support surface, and modulates the electron density around Rh, thereby substantially boosting N2O decomposition capability. The catalyst also demonstrated excellent stability, maintaining essentially constant conversion over 40 h of reaction. These findings underscore the potential of alkaline earth metal oxide doping as an effective strategy for designing high-performance noble metal catalysts for N2O abatement.