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Design of 2D Nanocrystalline Fe2Ni2N Coated onto Graphene Nanohybrid Sheets for Efficient Electrocatalytic Oxygen Evolution

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journal contribution
posted on 06.11.2019 by Sung Hoon Kwag, Yang Soo Lee, Jooyoung Lee, Dong In Jeong, Seok Bin Kwon, Jung Hyeon Yoo, Seongwon Woo, Byeong Seok Lim, Won Kyu Park, Min-Jun Kim, Jung Ho Kim, Byungkwon Lim, Bong Kyun Kang, Woo Seok Yang, Dae Ho Yoon
We report successfully synthesizing two-dimensional (2D) and nanocrystalline (NC) Fe2Ni2N/rGO nanohybrid sheets (NHSs) via ammonolysis of as-prepared 2D Ni2.25Fe0.75[Fe­(CN)6]2/rGO precursors. We compared the electrochemical properties of the 2D-NC Fe2Ni2N/rGO NHSs as non-precious-metal nitride and graphene nanohybrid electrocatalysts for an oxygen evolution reaction (OER) with those of NiFe-based composition. The overpotential and Tafel plot of the 2D-NC Fe2Ni2N/rGO NHSs had their lowest values of 290 and 49.1 mV dec–1, respectively, at a current density of 10 mA cm–2 (0.1 M, KOH). The 2D-NC Fe2Ni2N/rGO NHS catalyst was stable under OER conditions, and X-ray photoelectron spectroscopy and scanning transmission electron microscopy confirmed the stability of the catalysts after electrochemical testing (24 h). The synergistic interactions between the transition-metal nitride and graphene represent unique 2D nanostructured, metallic properties, and graphene sheets with nanocrystalline Fe2Ni2N on them are significantly more efficient and active electrocatalysts. The presented strategy of transition-metal nitride/graphene hybrid nanostructures provides potential for more efficient and outstanding OER electrocatalysts.