PtCo/C Core–Shell Catalysts on Various Carbon Supports: Synthesis, Structure, and Activity in Oxygen Reduction Reaction

This study is concerned with examining the effect of carbon support type on the properties of PtCo/C core–shell materials synthesized via a three-step method for use as catalysts in the oxygen reduction reaction (ORR) in low-temperature fuel cells. The PtCo/C catalysts were examined using thermogravimetry, X-ray powder diffraction, transmission electron microscopy, total reflection X-ray fluorescence, X-ray photoelectron spectroscopy, the low-temperature nitrogen adsorption technique, cyclic voltammetry, and linear sweep voltammetry. The results revealed variations in the composition, structure, and ORR catalytic activity of the materials depending on the type of initial support. The PtCo/C core–shell materials synthesized on an N-doped KetjenBlack EC-300J support exhibited the largest active surface area (over 100 m2/g(Pt)), a high specific activity of approximately 500 A/g(Pt) at a potential of 0.9 V, and the most positive half-wave potential of 0.93 V. These characteristics significantly surpass those of a commercial Pt/C analogue. Testing of the synthesized PtCo/C catalyst on a doped carbon support within a membrane electrode assembly confirmed enhanced catalytic activity compared to that of its commercial counterpart. Thus, this study demonstrates that the use of an N-doped support for depositing bimetallic PtCo core–shell nanoparticles through multistage wet synthesis significantly improves the performance of cathode catalysts for proton-exchange membrane fuel cells.