A one-step way to novel carbon-niobium nitride nanoparticles for efficient oxygen reduction

In recent years, researchers have been exploring various Pt-free electrocatalysts to optimize the performance of regenerative fuel cell and rechargeable metal-air battery. However, similar studies in ceramic fields are still stalled. In this work, as an efficient oxygen reduction reaction (ORR) catalyst, carbon-niobium nitride (C-NbN) nanostructure was successfully synthesized via a facile solid phase method. Microstructure characteristic analysis include SEM, TEM and element mapping spectra visually demonstrated C-NbN nanoparticles, and its unique carbon coating layer. Moreover, the state of the carbon layer of C-NbN was investigated by X-ray photoelectron spectroscopy (XPS), Raman scattering spectrum, and energy-dispersive X-ray spectroscopy (EDX). After a series of electrochemical tests, it was found that such a novel carbon layer play two important roles in the ORR, leading to superior ORR performance (with 0.9 V onset potential, vs RHE) and outstanding durability (retained 97.02% of initial current for a duration of 10 000 second chronoamperometry test and excellent methanol tolerance) of C-NbN catalyst. This method might could be implemented in the synthesis of other carbon-transition nitride ceramics to enhance their ORR performance.