Mathematical modeling of CO oxidation on Pd(100) at near-atmospheric pressures: Effect of mass-transfer limitations

• Published in: Surface science 2020-01, Vol.691, p.121488, Article 121488
• Main Authors: Makeev, Alexei G., Slinko, Marina M.
• Format: Article
• Language: English
• Subjects: Algorithms; Atmospheric models; Atmospheric pressure; Boundary layers; Carbon monoxide; CO oxidation; Computer simulation; Continuous flow; Crystal surfaces; Mass-transfer limitations; Mathematical modeling; Mathematical models; Matrix methods; Oscillations; Oxidation; Parameters; Planar laser induced fluorescence; Single crystals; Spatial distribution; Three dimensional models
• ISSN: 0039-6028; 1879-2758
• DOI: 10.1016/j.susc.2019.121488

•CO oxidation on Pd(100) in the mass transfer-limited regime was modeled.•PLIF experimental data were simulated with realistic values of kinetic parameters.•Inhomogeneous spatial distributions of CO and CO2 during oscillations were calculated.•The formation of a boundary layer near the catalyst surface was shown.•Metallic catalytic sites represent the most active phase on a partially oxidized catalyst. A 3D convection-diffusion-reaction model was developed to describe CO oxidation in a continuous-flow catalytic reactor containing a Pd(100) single crystal surface. The model was studied with the help of the pseudo-arclength continuation algorithm, which is based on a matrix-free Newton–Krylov method and enables a one-parameter continuation of stationary solutions of large systems. The model was used to simulate the 3D spatial distributions of CO and CO2 during “light-off” experiments and the oscillations in CO oxidation over Pd(100) detected by the planar laser-induced fluorescence (PLIF) method. With realistic values of parameters the developed model can reproduce almost quantitatively the experimental reaction rates and the PLIF images measured under steady-state conditions and during self-sustained oscillations under near-atmospheric pressure conditions. The formation of a boundary layer and the essential decrease of CO concentration near the Pd(100) single crystal surface were demonstrated after the catalytic ignition and in a high activity branch of the oscillatory cycle indicating the mass-transfer limited regime. [Display omitted]