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

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.