Towards breaking a linear scaling relationship in the fuel cell reaction: A theoretical study

초록

In PEM (Proton exchange membrane fuel cell), electrocatalyst for the oxygen reduction reaction (ORR) is playing a pivotal role in dictating their overall performance. A promising material for cathode has not yet been discovered, and a platinum catalyst is considered as the best. However, their high cost and low reaction rate are the main hurdles to PEM’s commercialization. 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 with the reaction sluggishness. Substantial enhancements in ORR activity requires the destabilization of key intermediate OH* independent of oxygen adsorption.[1-3] Our theoretical calculations show that the iron doped platinum sub-nanometer size clusters satisfy this prerequisite by binding OH* significantly weaker than oxygen compared to the platinum metal surfaces. This change in adsorption behaviour is related to change in chemical softness. We have used the Nørskov procedure for electrocatalytic activity, which confirmed the exceptional activity of iron doped platinum clusters.