X-ray absorption fine structure

Chemistry

Materials science

Electrochemistry

Engineering

Nanosheet

Physics

Electrode

Anode

Nanotechnology

Tafel equation

Spectroscopy

Quantum mechanics

Overpotential

Oxygen evolution

Chemical engineering

Physical chemistry

Angewandte Chemie International Edition

Iron‐substituted CoOOH porous nanosheet arrays grown on carbon fiber cloth (denoted as Fe x Co 1−x OOH PNSAs/CFC, 0≤x≤0.33) with 3D hierarchical structures are synthesized by in situ anodic oxidation of α‐Co(OH) 2 NSAs/CFC in solution of 0.01 m (NH 4 ) 2 Fe(SO 4 ) 2 . X‐ray absorption fine spectra (XAFS) demonstrate that CoO 6 octahedral structure in CoOOH can be partially substituted by FeO 6 octahedrons during the transformation from α‐Co(OH) 2 to Fe x Co 1−x OOH, and this is confirmed for the first time in this study. The content of Fe in Fe x Co 1−x OOH, no more than 1/3 of Co, can be controlled by adjusting the in situ anodic oxidation time. Fe 0.33 Co 0.67 OOH PNSAs/CFC shows superior OER electrocatalytic performance, with a low overpotential of 266 mV at 10 mA cm −2 , small Tafel slope of 30 mV dec −1 , and high durability.

Activating CoOOH Porous Nanosheet Arrays by Partial Iron Substitution for Efficient Oxygen Evolution Reaction