| Fuel cell as a portable energy converter has attracted considerable attention for a long time, which directly converts chemical energy into electric energy. The practical application of fuel cell is limited by the low kinetics, even for conventional Pt-based catalysts, and the high cost of using precious metal. Oxygen reduction reaction (ORR) is the most important reaction in fuel cell systems, which leads to the major potential drop. The alkaline fuel cell (AFC) uses alkaline solution as the electrolyte so it is less corrosive than the popular proton exchange membrane fuel cell (PEMFC). As a result, some non-precious materials can work as the electrodes to lower the cost of fuel cells, making AFC an attractive alternative for PEMFC. In this dissertation, a combined density functional theory (DFT) and kinetic Monte Carlo (KMC) has been developed out to well describe the reactions under complex electrochemical environment and fully understand the mechanism of ORR on Pt-, Ag- and Au- based catalysts. Our study ranges from the in-depth mechanistic understanding on monometallic systems to rational catalyst optimization using bimetallic and composite materials, in order to promote ORR activities and catalytic stability. |
