The Carbon Dioxide-Water Interface at Conditions of Gas Hydrate Formation

The structure of the carbon dioxide−water interface was analyzed by X-ray diffraction and reflectivity at temperature and pressure conditions which allow the formation of gas hydrate. The water−gaseous CO2 and the water−liquid CO2 interface were examined. The two interfaces show a very different behavior with respect to the formation of gas hydrate. While the liquid−gas interface exhibits the formation of thin liquid CO2 layers on the water surface, the formation of small clusters of gas hydrate was observed at the liquid−liquid interface. The data obtained from both interfaces points to a gas hydrate formation process which may be explained by the so-called local structuring hypothesis.