12-15 July 2011
Saint George Hotel
Africa/Johannesburg timezone

xygen adsorption on (110) surfaces of Pyrolusite MnO<sub>2</sub> and Anatase TiO<sub>2</sub>

13 Jul 2011, 17:00


Poster Presentation Track A - Condensed Matter Physics and Material Science Poster1


Ms khomotso Maenetja (University Of Limpopo)


Recent studies have employed manganese dioxide (MnO2) catalysts to improve the efficiency of Li-air batteries, while other studies have revealed that the Li/O2 cell can be recharged with high efficiency without a catalyst using an appropriate porous carbon electrode. Interestingly, charge voltages of these cells are similar to those of the MnO2, while both of these exhibits higher charge voltages than the cobalt-catalyzed cells. However, it has been observed that in the absence of a catalyst the recharge occurs at about high voltage, a large hysteresis between charge and discharge voltages. Ab initio planewave pseudopotential method will be used to investigate the interaction of the oxygen molecule with the (110) surfaces of MnO2, in particular tendencies of oxygen reduction. Their surface and adsorption energies were determined together with the distances between O-O of the oxygen molecule, in the vertical and horizontal orientation, the metal and oxygen molecule before and after relaxation. We found that manganese dioxide is more effective and gave lowest adsorption energies, and reduces oxygen molecule better than titanium dioxide. However the horizontal orientation of the oxygen molecule is more favourable in terms of oxygen reduction than the vertical orientation.

Level (Hons, MSc, <br> &nbsp; PhD, other)? MSc
Consider for a student <br> &nbsp; award (Yes / No)? Yes
Would you like to <br> submit a short paper <br> for the Conference <br> Proceedings (Yes / No)? No

Primary author

Ms khomotso Maenetja (University Of Limpopo)


Prof. Phuti Ngoepe (University Of Limpopo) Mr Seshupo Mangwejane (University Of Limpopo)

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