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 800oC 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 1g·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 800oC with 1, 5 and 10vol% 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.