Thickness-tunable core–shell Co@Pt nanoparticles encapsulated in sandwich-like carbon sheets as an enhanced electrocatalyst for the oxygen reduction reaction

Abstract

Despite enthusiastic research for platinum-based catalysts in past decades, these catalysts still lack long-term durability for the oxygen reduction reaction due to etching of the nonprecious metal in acidic electrolytes. Herein, we report a facile method for compounding two-dimensional sandwich-like Co/C samples with a series of different thicknesses of Pt layers, based on a seed-mediated growth method in chloroplatinic acid solution. There is only a 12.7% specific activity loss after 40 000 potential cycles. The sample exhibits super-high durability activity compared with other CoPt alloy catalysts under the same test conditions, benefiting from a great carbon layer maskant and Pt shell protection. According to density functional theory calculations, the nonprecious metal core has an indispensable role in adjusting the surface Pt atom and enhancing the activity for the oxygen reduction reaction. Our studies represent a robust method to design a core–shell structure with an ultralow content of Pt and improve the oxygen reduction reaction activity by tuning the nanoparticle architecture.