Impact of iron nitride-encapsulated bimetallic nickel molybdenum nitride on water-splitting efficiency in alkaline electrolytes

Abstract

The fabrication of highly active, reliable, and effective electrocatalysts for water electrolysis systems is essential for the development of sustainable energy conversion systems. In this context, interstitial nitrides can be used as inexpensive electrocatalysts for industrial water electrolysis due to their high electrocatalytic activity and high current density. This study reports the encapsulation of NiMoN with thin layers of iron nitride nanosheets, with the resulting catalyst (referred to as FeNiMoN) exhibiting an excellent overall water-splitting performance in an alkaline electrolyte. The interfacial modulation of NiMoN with iron nitride nanosheets modified its electronic structure, with the porous iron nitride improving the reactivity of the active NiMoN sites by facilitating the diffusion of the electrolyte. The prepared electrodes with the 1FeNiMoN//3FeNiMoN configuration achieved a stable current density of 10 mA at 1.49 V. The water electrolysis performance of the 1FeNiMoN//3FeNiMoN was also tested using multistep chronopotentiometry, producing excellent electrochemical results with high durability, surpassing recently reported NiMoN-based electrodes. Collectively, these results demonstrate that iron nitride encapsulated NiMoN are a promising material for use in bifunctional electrocatalysts for water-splitting applications.