Speaker
Level for award<br> (Hons, MSc, <br> PhD)?
MSc
Apply to be<br> consider for a student <br> award (Yes / No)?
yes
Main supervisor (name and email)<br>and his / her institution
Prof P.E Ngoepe, phuti.ngoepe@ul.ac.za, University of Limpopo
Would you like to <br> submit a short paper <br> for the Conference <br> Proceedings (Yes / No)?
No
Abstract content <br> (Max 300 words)
Density Functional Theory (DFT) with the plane-wave (PW) pseudo-potential method within the VASP code is employed to investigate the interaction of oxygen and water molecules on the synthetic nickel-rich pentlandite {100} and {110} surfaces. The oxygen-metal interaction show preferential iron oxidation than nickel on both surface models. However, a bridging of the oxygen molecule between the Fe-Ni metals on the {100} surface prefers the horizontal orientation with strong adsorption energy of -5.60 eV, while the un-oxidized nickel atoms dissociates into the sub-surface. We also observe a peroxo isomer anion (Fe (O2) -) species on the {100} surface with one oxygen forming a bridging bond with the nearest nickel atom. Moreover, the iron preferential oxidation is clearly seen on the {110} surface with the vertical orientation, where it moves towards iron forming a bridge. The oxidation of the nickel atom showed the presence of superoxo isomer species on the {110} surface. The hydration of nickel on {100} surface gives the most stable surface compared to {110} with a strong adsorption energy of -2.96 eV (exothermic) and while endothermic process is observed for the {110} surface (0.14 eV). However, hydration of {110} surface, in particular on the iron atom shows weak adsorption energy -0.07 eV (exothermic).
