Cathodized Stainless Steel Mesh for Binder-Free NiFe<sub>2</sub>O<sub>4</sub>/NiFe Layer Double Hydroxides Oxygen Evolution Reaction Electrode

Abstract

Oxygen evolution reaction (OER) is an essential reaction commonly applied in various energy storage and conversion technologies. One of the common issues of OER lies in its low kinetic activity. Therefore, developing durable, low-cost, and high-performance OER catalysts is critical. Recently, many attempts have used stainless steel mesh (SSM) as the substrate for OER electrodes because SSM is abundant, cheap, and durable. Nickel/iron-based materials, i.e., NiFe2O4/NiFe layer double hydroxides (LDHs), are regarded as one of the most excellent OER catalysts in alkaline electrolytes, making them attractive low-cost materials for OER catalysts. However, synthesizing NiFe2O4/NiFe LDHs directly on the surface of SSM is challenging. Modifying the SSM surface through cathodization has proved to enhance the adhesion and OER activity. Moreover, the cathodization technique is facile and cost-effective. In this work, the surface of SSM is modified by cathodization treatment. Subsequently, NiFe2O4/NiFe LDHs are deposited onto the surface of treated SSM via a low-temperature one-step chemical bath deposition technique. This synthesis is a binder-free method; the resulted electrodes show excellent OER performance without the binder effects. The as-prepared electrodes have a small Tafel slope of 125.4 mV/dec (1 M KOH) and high durability (10 mA/cm2 for 50 hours).