The reaction between carbon monoxide and oxygen on cuprous oxide at room temperature

Abstract

The catalytic reaction has been studied on a granular surface of the metal coated with cuprous oxide. The nature of the adsorbed species in the stationary state of the reaction has been investigated by measurements of heats of adsorption and by B. E. T. measurements. The adsorption characteristics of cuprous oxide have been compared with those of cupric oxide, and some measurements have been made of the heats of adsorption of hydrogen, ethylene and sulphur dioxide on cuprous oxide. The differential heat of adsorption of oxygen during the formation of the first few layers of cuprous oxide on copper metal has been determined. A constant value of 55 kcal is obtained after the first few layers have been built up. The adsorbed oxygen reacts with carbon monoxide and dioxide, giving a CO 3 complex as an intermediate stage in the reactions. The properties of this complex have been studied by calorimetric methods and it has been shown to be unstable in the presence of carbon monoxide. The reactivity of the adsorbed oxygen decreases with time, and it is concluded that this is due to the diffusion of Cu + ions to the surface, which partially builds the oxygen ions into the lattice. The steps in the reaction mechanism of the catalytic reaction have been formulated, and it is shown that in the stationary state carbon monoxide, oxygen ions and a C0 3 complex are present on the surface, the last two species being present in small amount. An explanation is given of the dependence of the reaction on the oxygen pressure.