Fine Tuning of the ORR Performance-Durability for Pt-Based Electrocatalysts

Abstract

The progress in the ORR electrocatalysis over the last two decades has been achieved primarily through the fundamental understanding of processes that are taking place at well-defined surfaces. For instance, the nature of active sites is a common topic in the literature, however, despite decades of persistent studies aimed to reveal the fundamentals, insight at atomic level is still lacking. Properties such as surface crystallographic orientation, morphology, composition and defects are yet to be assigned to the correlation between the atomic structure and catalyst activity. For the first time, we report on the atomic structure that has been investigated in combination with durability. The ultimate precision that goes beyond a part per million of a single atomic layer has been achieved in determining electrocatalytic properties of the ORR catalysts. Obtained knowledge is of paramount importance in design of advanced highly functional nanoscale materials. Surfaces of Pt-based materials have been characterized by AES, LEED and UPS, which was followed by controlled transfer to electrochemical, in-situ FTIR and STM cells. These findings have been further used to optimize a unique RDE coupled ICP-MS system. Such effort has led towards the design and synthesis of nanoscale materials with superior electrocatalytic properties. Fine tuning of the surface properties induced unprecedented improvements in functionality of real world catalyst for the ORR in fuel cells that will be reported for the first time.