Chromium Oxynitride (CrON) Nanoparticles: an Unexplored Electrocatalyst for Oxygen Evolution Reaction

Development of stable and efficient non-noble metal-based catalysts for oxygen evolution reactions (OERs) continues to pose a significant challenge owing to sluggish reaction kinetics (since it commonly involves four electron processes and O–O bond formation). Transition metal nitrides and oxynitrides are of particular interest in energy conversion and storage technologies due to its unique properties like metallic conductivity, wettability, durability, and chemical stability. However, chromium oxynitride is less explored as a catalyst for OER. In this work, we report chromium oxynitride (CrON) nanoparticles with spherical morphology, which are tested for electrocatalytic OER activity for the first time. The study is also conducted with its corresponding nitride (chromium nitride (CrN)) and oxide phase (chromium oxide (Cr2O3)) to benchmark the OER performance of the oxynitride. CrON nanoparticles show superior OER electrocatalytic properties over its corresponding nitride (CrN) and oxide (Cr2O3) material. CrON nanoparticles exhibit an overpotential of 409 mV at a current density of 10 mA cm−2, with a Tafel slope of 157 mV dec−1, and offers good stability for over 12h in alkaline medium. These values are lower than that of CrN (overpotential of 446 mV at 10 mA cm−2, and Tafel slope of 162 mV dec−1), and Cr2O3 (overpotential 477 mV and Tafel slope 210 mV dec−1). Graphical abstract: [Figure not available: see fulltext.].