Novel Pathways for Improving the ORR Rate

Technologies such as fuel cells and lithium-air batteries rely on electrochemical processes that need to provide satisfactory energy density; however, a major challenge lies in the insufficient activity and durability of materials that are currently employed as cathode catalysts for electrochemical reduction of oxygen.  These limitations inevitably lead to a lower operating efficiency of the devices, which highlights the need for development of more active and durable oxygen reduction reaction (ORR) catalysts.  Consequently, the majority of research efforts are placed on the catalyst design and synthesis aiming to improve their efficiency.  It has been found that properties such as surface structure, surface and subsurface composition associated with electronic properties have distinguished roles in determining functional properties of electrocatalysts ¹.  In this report the material-by-design-approach, would be used to demonstrate how the knowledge obtained from the well-defined surfaces can be employed to create tailor-made practical catalysts with advanced catalytic properties ².  Considering the fuel cells, most of the research is centered on platinum, the best monometallic catalyst for the ORR.  However, multimetallic systems could provide additional benefits by bringing together highly diverse constituents to alter and tune both catalytic activity and durability of the catalysts ³. 

            In addition to the catalyst's material it is of paramount importance to emphasize the role of liquid phase which is influencing on the overall properties of an electrified interface.  Molecular species from employed electrolyte and the nature of their interaction with the catalyst surface can be also used in tuning the catalytic performance.  More recently, it was also demonstrated that molecular patterning could be used as a tool that can induce selectivity of the electrocatalyst ⁴.

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