SYSTEMATIC THEORETICAL-STUDY OF ALLOYS OF PLATINUM FOR ENHANCED METHANOL FUEL-CELL PERFORMANCE

The ability of substitutional atoms in the (111)Pt surface to attract a water molecule and activate the formation of OHads on them is calcul ated using the ASED-MO theory. OHads is believed to be the oxidant tha t removes the CO poison from Pt anode surfaces in organic fuel cells. A total of 42 alloying atoms is treated, Sc through Se from period 4, Y through Te from period 5, and La through Po from period 6. As surfac e substitutional atoms, no elements to the right of the Pt group are f ound to attract H2O strongly enough to activate OH dissociation. Some of these elements, including Sn, are known to be active in the electro catalytic oxidation of COads but are believed to be atoms or complexes on or near the Pt surface. Of the elements to the left of the Pt grou p, a number from the first and second transition series attract and ac tivate H2O with comparable or greater effectiveness than Ru, a known a ctivator when present on Pt electrode surfaces. Whether these can be m ade stable alloy surfaces for organic fuel cell operation is an experi mental issue. Past experimental work in the literature suggests promis e for some of them.