Microkinetic model studies of alloying effects on the CO+NO+O2 reactions over Pt-Rh nanocatalysts

Microkinetic model has been used to study the kinetics of CO+NO+O 2 reactions on Pt-Rh nanocatalysts. The alloy particles show an intermediate behavior for the CO+O 2 reaction. For the CO+NO reaction, the kinetic behaviorof alloy particles are close to that of Rh, while for the CO+NO+O 2 reaction, it is very close to that of Pt. The rate of CO+O 2 and CO+NO+O 2 reactions is higher than that of CO+NO reaction on Pt, Rh and Pt-Rh nanocatalysts. The light-off temperature in case of CO+NO reaction is delayed in the absence of oxygen. The overall kinetics of the CO+NO+O 2 reaction on Rh is dominated by CO+NO reaction kinetics rather than by CO+O 2 reaction kinetics which has a higher inherent rate. The scenario reverses itself on Pt nanoparticles. The magnitude of the NO inhibition effect on the CO oxidation by O 2 is considerably smaller on Pt than on Rh. The simulated results are in qualitative agreement with the experimental findings.