Iron‐Cobalt‐Cerium Multimetallic Oxides Derived from Prussian Blue Precursors: Enhanced Oxygen Evolution Electrocatalysis

Abstract Exploring non‐precious metal‐based electrocatalysts is still challenging in 21 st century. In this work, a series of hexagonal bipyramidal Ce‐based PBA materials as precursors with different Fe/Co metal ratios, namely as CeFe x Co 1−x ‐PBA, are successfully constructed via co‐precipitation method and converted into corresponding metal oxides (denoted as Fe x Co 1−x CeO y ) via thermal treatment. Then, they as electrocatalysts realize highly efficient oxygen evolution reaction (OER). Especially, as‐synthesized Fe 0.7 Co 0.3 CeO y electrocatalyst shows very low overpotentials of 320 mV at the current density of 10 mA cm −2 and the Tafel slop of 98.4 mV dec −1 in 1 M KOH with remarkable durability for 24 h, which was due to the synergistic effect of multi‐metal FeCoCe centers. Furthermore, a two‐electrode cell of Fe 0.7 Co 0.3 CeO y /NF||Pt/C/NF realizes outstanding overall water splitting with a voltage of only 1.71 V at 10 mA cm −2 and remarkable long‐term durability, that is even superior to benchmark IrO 2 /NF||Pt/C/NF counterpart.