A new catalyst design strategy based on optimizing electronic structure has been proposed and then applied to a very important environmental application, the design of selective, sulfur-resistant oxidation emissions catalysts. The modified d-band center model developed by us in a previous study, to-ether with an energy decomposition scheme, is used to correlate measures of reactivity with reaction barriers of SO2 + O -> SO3 and NO + O -> NO2 on surfaces. Our objective is to find a catalyst which is active in oxidizing NO to NO2 but relatively inactive in oxidizing SO2 to SO3. The Ir alloyed Pt(111) surface is found to have the highest selectivity for oxidation of NO over SO2 at 700 K. Unfortunately, there is a slope change in the correlation of the weighted d-band center with the adsorption of NO at the transition state, which narrows down the range of the theoretical selectivity. Our ongoing study aims at understanding the reason for this. The general importance of this study for surface catalysis is also discussed.