Design of amorphous noble metallic nanoparticle electrocatalysts is an important fundamental and applied research challenge. Here, we describe new findings of a detailed investigation of the amorphous platinum nickel phosphorus nanoparticles supported on carbon (PtNiPa/C), which were characterized using X-ray diffraction, transmission electron microscopy, selected area electron diffraction. Compared to the crystal platinum nickel phosphorus nanoparticles supported on carbon (PtNiPc/C) and PtNi/C, PtNiPa/C catalyst has more positive half-wave potential and higher mass activity for oxygen reduction reaction (ORR). In addition, the ORR on PtNiPa/C electrode follows the 4 electron reaction pathway. (C) 2014 Elsevier B.V. All rights reserved.