Preparation, characterization and electrochemical evaluation of Ni–Pd and Ni–Pd–Pt nanoparticles for the oxygen reduction reaction

Abstract

The aim of this work is the development of a bimetallic nanocatalyst based on Ni–Pd and a trimetallic nanocatalyst with low Platinum content (Ni–Pd–Pt). Both materials were electrochemical evaluated to study their catalytic activity towards the oxygen reduction reaction (ORR). The Ni80Pd20/C catalysts were produced by two consecutive steps: 1) reduction of the Nickel precursor followed by, 2) galvanic displacement for Pd deposition and by the addition of small amounts of Pt (20 wt.% with respect to Ni–Pd), to obtain carbon supported (Ni80Pd20)Pt20/C nanocatalyst. The synthesized powders were characterized by X-ray Diffraction (XRD) and Scanning Transmission Electron Microscopy (STEM). Results indicate that the synthesis led to formation of a new phase in the bimetallic catalyst associated to the incorporation of Pt with an average particle size of 4.35 ± 1.0 nm. The electrochemical characterization shows that the addition of a second non-noble metal (Ni) to Pd slightly increases the catalytic activity towards the oxygen reduction reaction; however, when a small amount of Pt is incorporated to the Ni–Pd nanocatalyst to form a trimetallic catalyst the specific and the mass activity were increased by a factor of 2.5 and 3, respectively.