The platinum (Pt) has been considered as best candidate for electrocatalysts in oxygen reduction reaction because of the excellent intrinsic properties. Although the fuel cells that used Pt catalysts are success in commercialization, the limitation of total amount of Pt and the high price are rising problems to fuel cell market. To overcome this problem, researches explored another platinum group metals (PGM) such as palladium, iridium, ruthenium, and etc. Among the PGM, palladium (Pd) has been considered most efficient electrocatalysts as an alternative of Pt. Despite of the comparable electrochemical activity of Pd, it is vulnerable to liquid electrolyte and fuel gases under electrochemical reactions that lead to degrade the catalytic activity. Pd and nickel (Ni) alloys have been conducted to enhance the durability of Pd catalysts because Ni help to alleviate oxidation of Pd. Furthermore, nitrogen atoms were introduced for more stable M-Ni catalysts by inducing Ni4N species, but the structural analysis as well as the function of nitrogen were not fully understood yet. In this work, we synthesized nitriding introduced PdNi (PdNiN) alloy catalysts for the oxygen reduction reaction (ORR). The PdNiN nanoparticles were composed of monolithic antiperovskite structure (PdxNi1-xNNi3, ABX3), which is not reported so far. The antiperovskite structure was evaluated by Rietveld refinement from high resolution x-ray power diffraction and transmission electron microscopy. The unique Pd doped antiperovskite structure possessed high ORR activity and stability, which is comparable to the commercial Pt/C, in acidic medium. As a Pt-free Pd-based electrocatalysts, consequently, our results will be discussed with sufficient experimental and computational investigations.

Palladium-based antiperovskite as highly stable and efficient electrocatalysts for oxygen reduction in fuel cells

2019 Spring National Meeting

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