Hollow molybdenum carbide sphere (HMoCS) is synthesized by dispersing MoC particles in the shell of hollow carbon spheres. The typical HMoCS has the specific surface area of 542 m(2)/g, small-sized MoC particles of 15 nm in diameter and hollow spherical structure, which favor mass transfer and dispersion of smaller Pt particles, and then lead to excellent catalytic activity and stability of the Pt/HMoCS electrocatalyst for both ORR and MOR. In addition, the electron transfer or interaction force between MoC and Pt is believed to be the origin of the smaller Pt particles and the promotion effect of HMoCS on Pt. (C) 2015 Elsevier B.V. All rights reserved.