Adsorption of Hydrogen and Carbon Monoxide on Oxide Catalysts

Abstract

IN the course of experiments on the heats of adsorption of hydrogen and carbon monoxide on oxide catalysts, it was observed that these gases behaved in a curious manner on desorption. Hydrogen or carbon monoxide adsorbed at room temperature on the ZnO – Cr₂O₃ catalysts at equilibrium pressures of 10⁻³–10⁻⁴ cm. was evolved on raising the temperature to 100°–120°, but within a period of 20–30 minutes, it was readsorbed on the surface giving a hard vacuum in the containing vessel. On further raising the temperature, no gas was evolved until 350° C., when water vapour or carbon dioxide respectively was liberated. Mixtures of hydrogen and carbon monoxide behaved similarly, being evolved and readsorbed at 100°–120° C. and finally at 350° C. being converted into a mixture of water and carbon dioxide, no appreciable quantities of organic compounds being formed.