Distinct structure-activity relationship and reaction mechanism over BaCoO₃/CeO₂ catalysts for NO direct decomposition

The dependency on morphology is crucial for achieving highly efficient direct decomposition of NO. Herein, a BaCoO₃/CeO₂ catalyst is synthesized using CeO₂ small particles (p), spheres (s) and rods (r) as supports. The NO conversion to N₂ (NTN2) at 800 °C follows the order BaCoO₃/CeO₂-r (78.8 %) > BaCoO₃/CeO₂-s (75.9 %) > BaCoO₃/CeO₂-p (56.9 %) > BaCoO₃ (8.6 %) at a space velocity 1 g s/cm³. BaCoO₃/CeO₂-r exhibts high tolerance to O₂ and stability with conversion decreasing from 78.8 % to 74.6 %, 60.0 % and 50.0 % at 800 °C with 1, 5 and 10 vol% O₂, respectively. The high redox activity, higher active oxygen mobility and NO adsorption capability ensures its superior performance, while the high surface area (31.29 m²/g) and uniform distribution of active sites on the surface further promote the activity. The mechanism of NO direct decomposition is elucidated by in situ Diffuse reflectance infrared Fourier transform spectroscopy, ¹⁸O₂ isotopic transient exchange experiments and density functional theory (DFT) calculation.