Development of metal-doping technique in octahedral platinum-nickel catalysts on carbon supports for oxygen reduction reaction in proton exchange membrane fuel cells

Abstract

Octahedral Pt3Ni on carbon supports (Pt3Ni/C) are well-known to be excellent electrocatalysts for the oxygen reduction reaction (ORR) due to their exceptional activity. Unfortunately, Pt-Ni octahedral nanoparticles have a low durability. As a result, this study will synthesize octahedral Pt3Ni/C electrocatalysts with enhanced catalytic activity and stability for the oxygen reduction reaction (ORR) by adding a third metal, M, such as Ga, Ag, Cu, Rh, Co, Fe, and Mo. The solid-state chemistry or gas phase synthesis catalyst method for doping a third metal to octahedral Pt3Ni has been developed using two different approaches, which are referred to as Co-impregnation (Pt3Ni-M) and Metal-doping (M-Pt3Ni). The particle shape and size distributions were almost identical with an average particle size of around 8-9 nm for both approaches. Furthermore, the electrochemical properties of ORR were tested using voltammetry technique, which revealed an increase in ORR catalytic activity and catalyst stability. As pristine sample, the Fe-Pt3Ni/C from Metal-doping exhibited the highest ORR catalytic activity. For accelerated durability test (ADT) of 16,000 voltage cycles, the Cu-Pt3Ni/C exhibited the most stable catalysts with the activity retention of 69.9%, which was 5.8 times more stable than the Pt3Ni/C catalyst (12.1%). In addition, when the same metal was used, it was discovered that the Metal-doping (M-Pt3Ni /C) approach provided superior ORR activity and stability than the Co-impregnation (Pt3Ni-M/C) technique.