Supervisors: Prof. Roy Johnston & Prof. Lynne Macaskie
The expensive platinum catalysts in the electrode are said to attribute 33-50% of the cost of the PEMFC. Furthermore, these catalysts are prone to poisoning and degradation, leading to a reduction in the cell performance over time. To try and tackle these problems research is focused on two areas, the reduction in cost of electrocatalysts and the improvement of catalytic properties such as reaction kinetics and durability. To study nanoalloys simulations are performed on Pt based clusters of varying compositions alloyed with early transition metals in order to study catalytic activity.
Structural searches have been performed the Birmingham Cluster Genetic Algorithm coupled with emperical potentials as well as using the novel Genetic Algorithm coupled with DFT (GA-DFT) method. The range of sizes being studies is between a few to a few hundred atoms. This allows the study of size effects as well as compositional effects.
This research is focused on looking at stable structures and compositions of bimetallic clusters for improved catalytic properties. In order to study catalytic activity, adsorption of small molecules onto cluster surfaces is being simulated to study adsorption energies comparing to density of states characteristics. Following on from this, the Nugded Elastic Band method is used to compute reaction barriers.