Electrochemical Transformation of Metal Organic Framework into Ultrathin Metal Hydroxide-(oxy)hydroxide Nanosheets for Alkaline Water Oxidation

Electrochemical water oxidation requires a highly active electrocatalyst system with improved catalytic activity, high mechanical stability, and strong catalyst–support interactions. In this respect, a unique and facile method has been developed for the synthesis of ultrathin Fe–Co(OH) 2 –Co(O) x (OH) y nanosheets from self-supported Prussian blue analogues by chronoamperometric method. High electrochemical surface area, improved electronic conductivity, enhanced mechanical stability, and atomic level thickness (∼3 nm) of the self-supported ultrathin nanosheets provided the boost for alkaline water oxidation. The ultrathin Fe–Co(OH) 2 –Co(O) x (OH) y nanosheets demonstrated 10 mA cm –2 current density at only 250 mV overpotential for alkaline water oxidation. The ultrathin nanosheets also showed 24 h continuous oxygen evolution under chronoamperometric condition without losing the initial activity.