Inhibition effect of carbon dioxide on the oxidation of hydrogen over a platinum foil catalyst

Abstract

This paper investigates the catalytic ignition of the H(2)/O(2)/CO(2) mixture on platinum in a stagnation flow at atmospheric pressure experimentally and numerically. We measure the ignition temperatures of the gas mixtures flowing towards resistively heated platinum with various composition ratios and various diluent gases of N(2), Ar and CO(2). Compared with N(2) or Ar, the CO(2) dilution shows higher ignition temperature by about 50 K, even at the same composition ratio. The ignition temperature increase is proportional to the dilution ratio. Through the numerical simulation, it is illustrated that higher ignition temperature is caused by the adsorption of CO(2) and following dissociation on platinum surface, which was to date considered negligible in catalytic combustion. (C) 2003 Elsevier B.V. All rights reserved.