Effects of Pt content on the catalytic performance of Co@Pt/C Core-Shell structured electrocatalysts

Abstract

Core-shell structured Co@Pt/C electrocatalysts containing different mass fractions of Co to Pt, which are represented as 20% (w) Co@Pt(1:1)/C and 20% (w) Co@Pt(1:3)/C, were prepared by changing the ratio of metallic precursors using a successive reduction method. The structure and electrochemical performance of the as-prepared catalysts were characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), and linear sweep voltammetry (LSV). The performance of the as-prepared catalysts was compared with that of 40% (w) Co@Pt/C catalyst we synthesized previously. The sizes of Co@Pt(1:1) and Co@Pt(1:3) particles ranged from 2.2 to 2.3 nm, and the metal particles were well dispersed on the carbon support. The electrochemical specific area (ECSA) of 20% Co@Pt(1:1)/C (56 m2·g-1) and 20% Co@Pt(1:3)/C (60 m2·g-1) were higher than that of commercial 20% Pt/C (E-tek) (54 m2 ·g-1). Compared with those of 40% Co@Pt(1:1)/C and 40% Co@Pt(1:3)/C, the half-wave potentials of 20% Co@Pt(1:1)/C and 20% Co@Pt(1:3)/C shifted to the positive direction, and they correspondingly showed improved catalytic performance. The low cost and high performance of the 20% Co@Pt/C catalyst make it a promising low-Pt catalyst for proton exchange membrane fuel cells. © Editorial office of Acta Physico-Chimica Sinica.