The anodization of austenite stainless steel(SUS304) as a binder-free electrode for water electrolysis

초록

Anodization is known as the electrochemical method for obtaining functional metal oxide film on the valve metal surface such as aluminum, titanium, niobium, zinc and so on. Since anodized films with different adjustable morphologies show good physical/chemical properties, they have been widely used for diverse applications in the fields of energy storage electrode, catalysts, masks for lithography, membranes, bio-related applications and so on. In this study, we have prepared anodized film on stainless steel at the specific electrochemical condition, which shows ant-nest-like channels in the oxide films. Since the formed oxide is directly grown on the austenite stainless, it can be used as a binder-free electrode for various applications. We found that as-prepared oxide film consists of the transition metals such as Fe, Cr and Ni, being known as electrocatalysts of the water splitting containing hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). After stabilization of anodic oxide films by subsequent annealing process, water oxidation properties based on the anodized stainless steel have been carried out in 1.0 M KOH, showing that it provides enhanced performance of the HER and OER with a relatively small onset potential (?HER = 241 mV, ?OER = 287 mV at 10 mA cm-2) without the usage of noble catalysts.