(40e) Nanostructure Architecture of Pt Based Electrocatalysts for Energy Conversion Applications

Structure architecture at nanoscale is a challenging task to develop advanced nanomaterials.  Particularly in the electrocatalyst design for chemical-electrical energy conversion, it becomes critical in order to achieve both the targets of high catalytic activity and long durability simultaneously. Platinum (Pt) in the form of nanoparticles supported on high surface area carbon matrix is widely used for catalyzing the hydrogen/methanol oxidation reaction at the anode and oxygen reduction reaction (ORR) at the cathode of fuel cells today.  However, the precious metal Pt is not only expensive causing the high cost, but also scarce which limited the large scale application of fuel-cell technology. Moreover, Pt that is generally chemically inert becomes unstable when exposed to the hostile electrochemical environment where Pt surface atoms dissolve and migrate, resulting in aggregation of nanoparticles and losses of surface area, activity and power density. Particularly, the ordinary activity and degrading of Pt at the cathode represents one of the major limitations for commercialization of this technology.

Here I introduce our recent work on structure architecture of Pt-based nanoparticles for electrocatalytic applications. The particle size, shape, alloy composition and composite heterostructure were tuned with properties tailored for superior behavior in catalysis. The mechanisms of controlled nanoscrystal growth were depicted by molecular dynamic simulation and are thus able to be generalized to other system. Improvements in catalytic activity and stability were also explained by comparative studies on extended surfaces and first-principle calculations, which provided comprehensive understanding of the correlation between nanoparticle structure and catalytic performance. The developed strategy of combining state-of-the-art nanomaterial synthesis with fundamental study of model catalyst system and theoretical analysis represents a convictive approach toward advanced materials for catalytic and other applications.