DFT computation of Cu adsorption on the S atoms of sphalerite (110) surface

• Published in: Minerals engineering 2013-06, Vol.46-47, p.1-5
• Main Authors: Liu, Jian, Wen, Shuming, Chen, Xiumin, Bai, Shaojun, Liu, Dan, Cao, Qinbo
• Format: Article
• Language: English
• Subjects: Activation; Cu adsorption; DFT; Sphalerite
• ISSN: 0892-6875; 1872-9444
• DOI: 10.1016/j.mineng.2013.03.026

•Adsorption of Cu2+ ion on the surface S atoms of sphalerite was investigated.•Results show Cu2+ ion can be adsorbed onto the S atoms of sphalerite surface.•The adsorption belongs to chemical adsorption and activates sphalerite. The adsorption of Cu2+ ion on the various S atoms at sphalerite (110) surface was simulated using the density functional theory (DFT). The results of DFT indicate that Cu2+ ion can be readily adsorbed on the S atom of sphalerite (110) surface, i.e., Cu adsorption on the top site of S atom (top adsorption) and on the bridge site between two S atoms (bridge adsorption). The calculated adsorption energies for the top and bridge adsorptions of Cu2+ ion are −657.24kJ/mol and −670.11kJ/mol, respectively. The density of states (DOSs) analysis shows that a peak of Cu 3d orbital near to the Fermi level is formed after Cu2+ ion adsorption. The formed Cu 3d orbital peak and the S 3p orbital peak are overlapped between −2.00eV and 0eV, implying a steady chemical adsorption. Mulliken population analysis shows that the Cu atom was reduced with the resulting oxidation of the S and Zn atoms during the Cu adsorption process. A comparison of DOS between the Cu2+ ion adsorption and the Cu substitution for the top site Zn atom shows that the DOS of Cu2+ ion adsorption is very similar to that of Cu substitution. Thus, it was concluded that the adsorption of Cu2+ ion on the S atom of sphalerite surface can also result in the activation of sphalerite.