Pt-Based Core–Shell Catalyst Architectures for Oxygen Fuel Cell Electrodes

Pt-based core–shell nanoparticles have emerged as a promising generation of highly active electrocatalysts to accelerate the sluggish kinetics of oxygen reduction reaction (ORR) in fuel cell systems. Their electronic and structural properties can be easily tailored by modifying the Pt shell thickness, core composition, diameter, and shape; this results in significant improvements of activity and durability over state-of-the-art pure Pt catalysts. Prompted by the relevance of efficient and robust ORR catalysts for electrochemical energy conversion, this Perspective reviews several concepts and selected recent developments in the exploration of the structure and composition of core–shell nanoparticles. Addressing current achievements and challenges in the preparation as well as microscopic and spectroscopic characterization of core–shell nanocatalysts, a concise account of our understanding is provided on how the surface and subsurface structure of multimetallic core–shell nanoparticles affect their reactivity. Finally, perspectives for the large-scale implementation of core–shell catalysts in polymer exchange membrane fuel cells are discussed.