(182a) Novel Electrocatalysts with Advanced Nanoscale Architectures for Energy Conversion Applications

Highly efficient chemical-electrical energy conversion has become the primary target of the development of renewable energy technologies such as fuel cells and metal air batteries.  This to a large extent relies on advanced electrocatalysts with high catalytic activity, high durability, and competitive cost effectiveness.  Conventional catalysts comprising platinum (Pt) nanoparticles supported on carbon have rather low catalytic activity, and also expensive and scarce.  Moreover, Pt that is generally considered to be chemically inert becomes unstable when exposed to the hostile electrochemical environments.  Significant improvements in both catalytic activity and durability, and thus reduced usage of precious metal are thus desired for large-scale applications of these technologies. 

We have explored the rational design and synthesis of advanced Pt-based bimetallic (Pt-Ni, Co, Re) and multimetallic (Au/Pt₃Fe) electrocatalysts for the oxygen reduction reaction (ORR) – the key reaction in fuel cells and metal-air batteries.  Critical parameters including particle size, shape, alloy composition and element distribution were integrally designed for optimal catalytic performance for the ORR.  State-of-the-art electron microscopic and X-ray spectroscopic analysis were applied to characterize the fine core/shell nanostructures, which were further correlated to the catalytic performance revealed by electrochemical studies.  The combinational studies of model extended surfaces and practical nanocatalysts, plus additional theoretical calculation and simulation, represent a persuasive approach targeting the fundamental mechanisms of catalytic activity and durability enhancement.  Such an approach could also be generalized to the development of other functional materials in a rational way.