(212b) Maximizing the Mass Activity of Pt-Based Catalysts Toward Oxygen Reduction

Platinum is by far the best catalyst for the oxygen reduction reaction (ORR). Its low abundance, limited supply, and ever increasing price have kept motivating researchers to maximize the use of this precious metals. One effective strategy is to increase the utilization efficiency (i.e., the fraction of Pt atoms on the surface) by reducing the particle size and thus increasing the dispersion of Pt atoms. For this reason, commercial ORR catalysts are typically based upon Pt particles of only a few nanometers in size. Despite the extensive use, it has been difficult to optimize the specific activity of such tiny particles by engineering their surface structure through facet-controlled syntheses. Such minuscule particles also tend to sinter and/or be detached from the support, resulting in major deterioration in performance during the course of operation. In this talk, I will discuss a number of strategies for increasing the mass activity and durability of Pt-based ORR catalysts, including facet-controlled synthesis, increase of dispersion by forming open structures, surface strain engineering, electronic coupling through alloying, and use of particles with optimized dimensions.