Catalytic Activity of Pt-Fe Sub-nm Size Bimetallic Electrocatalyst for PEM Technology: A First Principle Study

초록

PEM (Proton exchange membrane fuel cell) is utilizing energy in the cleanest and the most efficient way. Fuel cells have already working in different places. However, their commercialization has been delayed by haggling over the platinum made electrocatalysts hitches and non-availability of suitable alternatives. The electrocatalysts with enhanced activities and long durability compared to Pt are urgently necessary for the fast replacement of current energy conversion devices, which have low efficiency and produce harmful byproducts. In PEM, electrocatalyst for the oxygen reduction reaction (ORR) is playing a pivotal role in dictating their overall performance. Our group found that the ORR electrocatalyst is hemmed in multidimensional problems i. e., low durability, efficiency in alkaline media, tolerance for CO, and more importantly slow reaction at the cathode. Solutions for these problems are not as straightforward as thought. The linear scaling relationship among the adsorption behaviour of different oxygen containing intermediates is an ultimate limitation to the catalytic competence. Subsequently, more platinum is used to cope the reaction sluggishness.Substantial enhancements in ORR activity requires the destabilization of key intermediate OH* independent of oxygen adsorption. For years, scientists have been working on the design of suitable electrocatalysts with minimum triumph. Regardless of advances in catalytic sciences, development of new catalysts is still a black art owing to lack of universal descriptor for catalytic activities. In this arena, first principles approaches seem to be the best way to filter, predict, and examine new electrocatalysts, and to suggest promising materials for testing and experimental verification. We have made systematic studies for iron-doped platinum sub-nm size electrocatalysts.