First-principles design of highly active and durable Ti55Cx@Pt92 nanocatalyst for oxygen reduction reaction through charge control at nanointerfaces

Abstract

Although the oxygen reduction reaction plays a key role in various chemical industries, its high kinetic barrier is a long-standing issue. The design of alternatives to Pt catalysts is in high demand owing to the material performance, durability, and cost-effectiveness. Here, we demonstrate that core-shell Ti55Cx@Pt92 nanoclusters are promising for substantial activation energy reduction as well as enhanced electrochemical stability in the oxygen reduction reaction. The transition metal carbide core compounds facilitate the activity of Pt shells with better durability than pure Pt nanoclusters via the hybridization of Pt-5d and Ti-3d. Quantum mechanical high-throughput screening enabled us to identify Ti55C44@Pt92 as a promising nanocatalyst with a significantly lower overpotential (0.37 V) than pure Pt147 (0.46 V) of approximately the same size. Using first-principles calculations, we located the underlying mechanism at a favorable charge distribution at the nanoscale interfaces between the core and shell, which cannot be described solely by the conventional model between the activity and electronic structure. Furthermore, the composition of carbon elements in the core was revealed as an important descriptor. Our results provide design principles based on rigorous structure-performance correlation in the nanoscale regime for electrocatalysts with high activity and long-term durability toward a specific target.