| dc.description.abstract | Platinum and platinum alloy surfaces are used as catalysts to promote the reduction of oxygen, one of the reactions used to generate electrical energy in low temperature fuel cells, which are sought as promissory clean power sources. In such devices, the oxygen reduction is the slowest of the two electrode reactions, significantly affecting the performance of the fuel cell. Oxygen reduction is also important for several biological problems, such as oxygen transport in living organisms. In my research, I analyzed the effect of concentrations of a secondary metal on the overall mechanism of oxygen reduction on platinum alloy catalysts. I employed dynamic Monte Carlo, a simulation program that studies the kinetics of reactions, and returns relevant data that can be analyzed.
To better understand how to improve the oxygen current density, I studied two different cases involving a bimetallic surface. For the first case I employed an initial secondary metal M at varying concentrations with a 100% increase in activation energy for the adsorption of oxygen, but a 10% decrease in activation energy for the other four electron transfer reactions, while the second case I kept the above values, but reduced the activation energy for the adsorption of oxygen to a 10% increase on metal M. I discovered that between 50 to 70% metal concentration enabled the best sites for reduction for the first case, and 50 to 90% metal concentration enabled the best sites for reduction for the second case. This is particularly important, for if it can be discovered that a secondary metal mixed with platinum can yield the results I discovered, then the reduction of oxygen may become commercially feasible, reducing the cost of the catalyst needed, and by increasing the current density yield resulting in greater reduction performance. | en |
