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![Recent advances in earth-abundant first-row transition metal (Fe, Co and Ni)-based electrocatalysts for the oxygen evolution reaction](https://image.oaes.cc/92b7fbf7-13f1-4589-b2f9-a2999bf9db55/5063.fig.1.jpg)
Figure 1. (A) XPS surface survey scan and high-resolution O 1s, N 1s, Fe 2p and Ni 2p spectra of Ni2Fe1@PANI-KOH900. (B) XRD patterns of Ni2Fe1-900, Ni2Fe1 NPN, Ni2Fe1@PANI-900 and Ni2Fe1@PANI-KOH900. (C) Schematic illustration of synthesis procedure for Ni2Fe1 NPN, Ni2Fe1@PANI-900 and Ni2Fe1@PANI-KOH900. (D) TEM (1), SAED (2) and HADDF-STEM (3) images of Ni2Fe1@PANI-KOH900. Reproduced with permission. Copyright 2019, Royal Society of Chemistry[48].