Oxygen vacancy-rich amorphous porous NiFe(OH) derived from Ni(OH)/Prussian blue as highly efficient oxygen evolution electrocatalysts.

Oxygen vacancies or defects play a significant role in improving the intrinsic activities of bimetallic hydroxides towards the oxygen evolution reaction (OER); however, their rational design and preparation remain a great challenge. In this study, oxygen vacancy-rich amorphous porous nickel iron hydroxide nanolayers supported on carbon paper (NiFe(OH)/CP) are rationally prepared through a facile approach involving the sequential electrochemical deposition of a Prussian blue (PB) nanocrystal layer and Ni(OH) layer on carbon paper followed by an alkaline etching process, where PB nanocrystals act as an Fe source and template for the formation of an amorphous porous NiFe(OH) layer. NiFe(OH)/CP with an ultralow loading of 0.