| Popis: |
State-of-the-art Density Functional Theory calculations are employed in the investigation of a number of processes occurring at the anode and cathode of Alkaline Fuel Cells for a variety of electrocatalyst materials. In the case of the methanol oxidation reaction, at the anode, the investigation is carried out with a view to quantitatively resolving the nature of the surface adsorbate on Pt(211) and is executed in combination with a cluster-continuum model approach, the principal adsorbate is found to be a methanol-OH complex. At the cathode, the oxygen reduction reaction is studied for the purpose of obtaining complete mechanistic understanding in the free energy landscape, thereby enabling the elucidation of the potential-determining step and, furthermore, the theoretical prediction of the onset potential. The oxygen reduction reaction is thus studied upon a range of cobalt oxide surfaces, and for a variety of Pt-WC catalysts, in addition to pure Pt(111}. The results obtained show good agreement with experiment, where appropriate. Furthermore, they highlight the need for detailed mechanistic studies in order to predict and explain experimental results since simplified, single-descriptor, approaches may sometimes result in misleading predictions. |
