Voltammetrically Deposited Nife on Modified Ni Foam As an Efficient and Stable Electrocatalyst for Oxygen Evolution Reaction

Environmentally safe and efficient production of renewable fuels are of great demand to meet the current global energy crisis and global warming. As a fuel, hydrogen has been considered as the most suitable source of clean and sustainable energy, which indeed promote the importance of electrochemical water splitting [1-3]. Efficient and stable electrocatalyst for both hydrogen and oxygen evolution reactions are inevitable for the commercialization of water electrolyzer. Comparatively, the oxygen evolution reaction (OER) is more sluggish than the hydrogen evolution reaction (HER), which in turn affect the overall efficiency of the water electrolysis [4]. The non-noble metal oxides-based catalysts in alkaline solution have been shown promising OER activity [5] however, the high alkaline condition and high oxidation potential affects the stability of the metal oxides. Bimetallic oxide of NiFe system has been found as an efficient catalyst for OER [6]. Various methods were demonstrated for the synthesis of NiFe catalyst and studied their OER activity. In the present work, we made NiFe catalyst through electrochemical deposition method. We deposited NiFe over Ni foam and modified Ni foam through the constant potential method and voltammetric method. The OER activity and stability of these catalysts were measured in alkaline solution. Among the various catalysts synthesized, the NiFe deposited over modified Ni foam through constant potential method has shown better OER activity, attained 10 mA/cm 2 at 1.45 V (vs RHE) but after electrolysis the potential increased to 1.47 V, indicating the poor catalytic stability. Whereas the NiFe catalyst prepared through the voltammetric method has attained 10 mA/cm 2 at 1.46 V and remained unchanged after electrolysis, indicating better catalytic activity and stability (Figure 1). Figure 1. Linear sweep voltammogram measured before and after electrolysis in 1 M KOH of electrodeposited NiFe catalyst prepared through (a) constant potential method and (b) voltammetric method . Acknowledgement This presentation is based on results obtained from a project commissioned by the New Energy and Industrial Technology Development Organization (NEDO) References. 1 N. T. Suen, S. F. Hung, Q. Quan, N. Zhang, Y. J. Xu and H. M. Chen, Chem. Soc. Rev. 46 , 337–365 (2017). 2 M. I. Jamesh and X. Sun, J. Power Sources . 400 , 31–68 (2018). 3 S. Jung, C. C. L. McCrory, I. M. Ferrer, J. C. Peters and T. F. Jaramillo, J. Mater. Chem. A . 4 , 3068–3076 (2016). 4 M. Tahir, L. Pan, F. Idrees, X. Zhang, L. Wang, J. J. Zou and Z. L. Wang, Nano Energy . 37 , 136–157 (2017). 5 F. Song, L. Bai, A. Moysiadou, S. Lee, C. Hu, L. Liardet and X. Hu, J. Am. Chem. Soc. 140 , 7748–7759 (2018). 6 M. Gong and H. Dai, Nano Res. 8 , 23–39 (2014). Figure 1