| Recent advances in electronic structure theory methods and surface science techniques are helping to rapidly bridge the gap between the lab and industrial setups for a variety of catalytic reactions. These tools have been successfully combined to explain atomic-level phenomena for different catalytic systems. The insights gained in this process are important for rational design of alloy catalysts for different reactions. With the imminent energy crisis, proton-exchange membrane fuel cells (PEMFCs) have emerged as environment-friendly energy conversion devices. Wide-scale commercialization of PEMFCs is, however, impeded by several technical challenges, including the efficiency of catalysts for related processes.;In this thesis, Density Functional Theory (DFT) calculations are used to understand the thermodynamics and kinetics of PEMFC-related catalytic reactions, including oxygen reduction reaction (ORR) at the PEMFC cathodes, hydrogen oxidation reaction (HOR) at PEMFC anodes, preferential oxidation of CO in hydrogen (PROX) and low-temperature water-gas-shift (WGS) reaction. Through a detailed analysis of the adsorption behavior of reaction intermediates and activation energies of relevant elementary reactions, key reactivity descriptors are identified: (i) binding energy of atomic oxygen and hydroxyl for ORR, (ii) differential binding energy of CO for HOR, and (iii) binding energy and saturation coverage of CO for PROX. Based on these principles, transition metal alloy catalysts are then designed, synthesized and characterized using a wide array of experimental techniques. Significant improvements in reactivity, cost and stability of catalysts thus developed are measured experimentally and explained using DFT calculations. Finally, extensions of these ideas for other catalytic processes are proposed, and suggestions for future work are presented. |
