Facile Synthesis of Nitrogen-Doped Carbon-Supported Rhodium–Cobalt Alloy Electrocatalyst for Oxygen Reduction Reaction

Abstract

Fuel cells are considered as efficient and environmentally ecofriendly alternatives for energy production. The oxygen-reduction reaction is important in energy-conversion systems for fuel cells. In this work, rhodium (Rh) and cobalt (Co) alloy nanoparticles were deposited on nitrogen (N)-doped carbon (C) supports (RhCo/NC) using ball milling and thermal decomposition. The RhCo/NC composites were transformed into small nanoparticles with an average diameter of approximately 4 nm. The properties of the as-synthesized RhCo/NC nanocatalyst were characterized through transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Raman spectroscopy. The catalytic activity of the nanocatalyst for the ORR was investigated. The RhCo/NC nanocatalyst showed good activity for the ORR, long-term durability in chronoamperometry tests, and resistance to methanol crossover in an alkaline solution. This was because of the synergistic effects of the metal alloy. Chronoamperometric analysis demonstrated the remarkable durability of the RhCo/NC nanocatalyst compared to a commercial platinum (Pt)/C catalyst. Moreover, the RhCo/NC nanocatalyst exhibited good methanol tolerance. The RhCo/NC nanocatalyst can replace Pt-based catalysts in energy-conversion systems.