Size-dependent oxygen reduction property of octahedral Pt–Ni nanoparticle electrocatalysts

Abstract

The size effect on the electrocatalytic property of octahedral Pt–Ni alloy nanoparticles in the oxygen reduction reaction (ORR) was studied by making particles with different sizes and conducting electrochemical measurements. Octahedral Pt–Ni nanoparticles on carbon support (Pt–Ni/C) were produced using a facile and surfactant-free solid-state chemistry method. Two groups of octahedral Pt–Ni/C, including Pt₃Ni/C and Pt_1.5Ni/C, with particle size ranging from around 4 to 8 nm were prepared. Both the ORR activity and the stability of the two group catalysts were studied, which exhibited varying dependence over the particle size. The different relationships between the Pt–Ni size and the ORR property were investigated and attributed to alterations in the particle electronic/geometric structure and the Ni leaching behaviour.