Vacancy Enriched Structurally Modulated Nickel Ferrite for Oxygen Evolution Reaction

Abstract

Generation of clean hydrogen fuel from renewable source like water by electrocatalytic water splitting is an advanced energy conversion technology. The idea of water splitting attracts the researcher to focus on the synthesis of active and stable catalysts. We modulated nickel ferrite using different surfactants and developed an active two-dimensional (2D), economic and sturdy catalyst for the study of oxygen evolution reaction (OER) in basic electrolytic solution. Nickel ferrite with CTAB named as NF(C), with ascorbic acid named as NF(A), with oxalic acid named as NF(O) and Nickel ferrite without surfactant is named as NF. NF(O) having 2D structure shows better catalytic activity among all. The catalytic activity of NF(O) was further enhanced through reduction process. We reduced NF(O) using hydrazine hydrate along with ultrasonication power treatment to induce vacancy in the material namely V_o-NF(O). V_o-NF(O) exhibits low overpotential of 260 mV at 10 mA/cm² with Tafel slope of 25 mV/dec and stability of 18 h. Creation of vacancy boosts the catalytic activity of the electrocatalyst by increasing the surface area and number of reactive sites of the catalyst, which improve electrical conductivity, thus facilitating the transfer of charges.