Highly durable core(Nb4N5)-shell(NbOx)-structured non-precious metal catalyst for oxygen reduction reaction in acidic media

In this study, we demonstrate an easy and eco-friendly synthesis method of Nb-based electrocatalysts using the combination of pulsed laser ablation in liquid and ammonia nitriding at various temperatures and times. Our electrocatalyst samples had a nanoparticle size with a core-shell structure, where the niobium nitride core was surrounded by a thin layer of niobium oxide shell. The nitriding conditions for the samples successfully modified the core structure to become more electrically conductive. The Nb4N5@NbOx/C_5 h, the sample heat-treated at 900 degrees C for 5 h, exhibited a moderate onset potential and catalytic activity. More importantly, the oxygen reduction reaction performance of the Nb4N5@NbOx/C_5h sample did not degrade over 10,000 potential cycles. Based on the above results, we suggest that the nitride core and the thin layer of the oxide shell might be responsible for oxygen reduction by facilitating electron transport and providing oxygen adsorption sites. (C) 2022 The Author(s). Published by Elsevier B.V.

Automated summary

In this study, a simple and eco-friendly synthesis method of Nb-based electrocatalysts was demonstrated using pulsed laser ablation in liquid and ammonia nitriding. The synthesized electrocatalyst samples had a nanoparticle size with a core-shell structure, showing improved electrical conductivity. The Nb4N5@NbOx/C_5h sample, heat-treated at 900 degrees C for 5 h, exhibited moderate onset potential and catalytic activity, with no degradation in oxygen reduction reaction performance over 10,000 potential cycles.