A molecular beam study of the kinetics of the catalytic reduction of NO by CO on Rh(111) single-crystal surfaces

摘要: Abstract Steady-state rates for the catalytic reaction of NO with CO on Rh(111) surfaces have been measured under isothermal conditions by using a molecular beam approach mass spectrometry detection. Systematic studies were carried out as function surface temperature, NO+CO composition, and total flux. A maximum in rate was observed between 450 900 K, exact temperature depending NO:CO ratio. Indeed, synergistic behavior seen where loss reactivity induced increasing concentration is partly compensated higher temperature. The data presented here are consistent rate-limiting step overall reduction process being recombination atomic nitrogen atoms resulting from fast dissociation adsorbed molecules. Temperature-programmed desorption titration experiments also performed after kinetic runs order to estimate coverages reactants during steady-state reactions. conversion found be directly proportional coverage oxygen surface. relation coverages, however, proved much more complex; an inverse correlation fact most cases those two parameters. build-up critical necessary trigger N 2 . This strongly held determined not depend any significant way composition beam, but decrease all cases.