Abstract
The heat of immersion of zinc oxide was studied, using a calorimeter. From the experimental results the following conclusions were obtained:
The heats of immersion of zinc oxidin water and in n-hexyl alcohol increase at about 300°C of the degassing temperature of the sample powder, and show a maximum at about 400°C. This is not brought about by either the heat of hydration of surface OH group or the heat of hydrogen bonding of the surface, as in the case of other oxides such as silica, alumina, or titania. The surface reaction acidic or basic centers does not cause the generation of heat of immersion in these systems;
In the systems of zinc oxide and water or n-alcohol, the heat of immersion depends on the heat of formation of an electrical double layer which accompanies the adsorption of protons;
The heat of immersion of zinc oxide in water or in n-alcohol depends on the amount of lithium and aluminum ions added and shows a fair dependency on the surface concentration of interstitial zinc atoms. Therefore, the adsorption center of the proton is considered to be the interstitial zinc atom on the surface.
