Heterogeneous Atomization of Hydrogen and Oxygen

Abstract

BECAUSE of its chemical simplicity, the process of atomization of hydrogen at a surface is free from many of the ill-defined parameters which are important in more complicated heterogeneous reactions and which make their interpretation equivocal. The reaction over tungsten was discovered by Langmuir¹ and investigated quantitatively by Bryce² and Ivanoiskaya and Mochan³. The experimental arrangement employed by these authors consisted of a tungsten filament suspended in hydrogen, the wall of the reaction vessel being coated with a hydrogen-atom trapping agent so that the reaction velocity could be determined by the measurement of the rate of fall in the pressure of hydrogen. Bryce used molybdenum oxide as the hydrogen-atom trap, while Ivanoiskaya and Mochan used potassium. They found that the rate of atomization was accurately proportional to √P in the pressure range 10⁻²–10⁻³mm. of mercury and the energy of activation (E) was 45 kcal./mol. or rather less.