Microkinetic model studies of impurity effects on CO + O2, CO + NO and CO + NO + O2 reactions over supported Pt–Rh nanocatalysts

Influence of sulphur on the catalytic activity of supported Pt50Rh50 nanoparticles for the CO + NO + O2 reaction has been studied through a microkinetic model. The turnover number of CO2 molecules per surface atom per second has been found, as expected, to decrease with increase in sulphur coverage. For the CO + NO reaction, the turnover number is smaller by 2–4 order of magnitude compared to the CO + O2 and CO + NO + O2 reactions. Irrespective of the sulphur coverage on the surface, the turnover numbers of CO2 molecules are found to be much higher than the turnover numbers of N2 molecules. Furthermore, the turnover number of N2 molecules for the CO + NO and CO + NO + O2 reactions are found to be identical under identical kinetic conditions.