First-principles study on the co-adsorption of water and oxygen molecules on chalcopyrite (112)-M surface

Abstract

Chalcopyrite is a common copper-bearing mineral with antiferromagnetic properties. However, this property has rarely been considered in previous studies for detailed adsorption behaviors of molecules on chalcopyrite. Based on density functional theory (DFT), new adsorption pathways by H2O and O2 on the chalcopyrite metal terminated (112) surface ((112)-M) is found in this work. First, through simulating the adsorption of an isolated water molecule and monolayer water molecules, it is confirmed that H2O molecules tend to adsorb on the surface Fe atoms more than on the surface Cu atoms. Then, we studied various adsorption behaviors of the O2 molecule. It is found that the adsorption on the hollow FeFe site is the most stable case; however, O2 is undissociated. Two adsorption cases will happen when H2OO2 adsorb simultaneously on the surface. For the S site, the H2O molecule thoroughly dissociated and formed SO species, and the other case is H2O undissociated adsorbing at the Cu site. For the former case, it is interesting that H2O is dissociated before O2.