Theoretical Study on the Interaction of O2 over the 110 Surface of Au and Its Effect on the Reaction of CN-

Cyanidation of gold depends on the amount of oxygen in the reaction medium. In this study, the interaction of O2 molecules with crystalline surfaces of gold (110surf0 and 110surf+1 surfaces) is investigated by using density functional theory (DFT). The results showed that the interaction of O2 with Au2 cluster was weak, which leads to overlapping orbitals of the 5dz2-Au and the pz-O2. Oxygen reacts vertically with the surface was almost similar to its reaction with the Au2 cluster. However, the parallel interaction of O2 on the (110surf0) and (110surf+1) surfaces of Au is stronger than the vertical interaction state. Also, the interaction energy of CN- with (110surf+1) surface obtained about 13 kJ/mol more than (110surf0) surface.