Enhancing the Hydrogen-Air Fuel Cell Performance of Octahedral Ptni Nanoalloys with Rational Design of Dopants, Layering and Support in the PEM Fuel Cells

Abstract

This study focuses on the scale-up synthesis of carbon-supported octahedral PtNiX nanoparticles to improve their oxygen reduction reaction electrocatalytic activity, stability, and high current density for fuel cell applications. Octahedral PtNiX nanoparticles doped with different elements such as Rh or Ir and with high Pt loading on carbon supports were synthesized, characterized by physio-chemical methods and tested in single MEA-based fuel cells after rotating disk electrode (RDE) pre-screening measurements. Different carbon supports were compared, including N-doped carbon. We investigated the sensitivity of the I/C ratio for the ink on the performance of the nanoparticles in RDE, and show that it is an important parameter to consider during synthesis. Our study shows that the sensitivity of the I/C ratio is more pronounced for PtNi alloy octahedra than for pure Pt catalyst. Moreover, we also use in-situ measurement techniques, such as X-ray Absorption Spectroscopy (XAS) in a liquid cell, to study the impact of the dopants during the operation. In the MEA, we achieve a state-of-the-art current density of around 1500 mA/cm2 at 0.6V for octahedral PtNiX nanoparticles in fuel cell applications. This high current density is attributed to the superior electrocatalytic activity and stability of the doped nanoparticles, as well as their high loading of Pt. Overall, our results demonstrate the potential of octahedral PtNiX nanoparticles as highly efficient electrocatalysts for fuel cell applications. The study highlights the importance of considering the I/C ratio during catalyst ink preparation, and the use of in-situ measurement techniques to improve the fundamental understanding of catalyst structure-activity and -stability for the design of future electrocatalysts.