The molten Ag in air is capable of dissolving 22 times its own volume of oxygen, but the amounts of other gases (N2, CO2 etc.) released from silver during the cooling and curing process are almost zero. Adsorption is known to be the first step of gas dissolution, so the adsorption behavior of N2, O2 and CO2, the main components of air, on the Ag surface was investigated by the method based on quantum chemical theory and clusters model. The results show that the adsorption energy of O2 on Ag (100), Ag (110) and Ag (111) is the largest, so the surrounding area of Ag in air is mainly adsorbed with O2 and almost no direct contact with other non-oxygen components can be observed. The dissociation of N2, O2 and CO2 on the Ag surface requires certain thermal activation conditions, and the dissociation energy barrier of O2 on the Ag surface is lower than that of N2 and CO2., As a result, O2 is more readily dissociated into O atoms which are adsorbed on the surface. Therefore, Ag can selectively adsorb O2 in air. |