From waste high speed steel alloy to valuable oxygen evolution reaction catalyst in alkaline medium

Abstract

An efficient, cost effective and stable electrocatalyst design and development is a bottleneck for the anodic oxygen evolution reaction (OER) in the electrochemical water splitting process. Herein, we have prepared a catalyst from high speed steel powder (HSSP) for OER in the alkaline medium (1 M KOH) which owns potential to replace the benchmark RuO2 catalyst. The HSSP was obtained through ball milling of high speed steel (HSS) alloy was characterized for physico-chemical and electrochemical catalytic properties. The physico-chemical characterizations reveal that HSS has Fe as major constituent and Cr, Mo, W, V and C as minor constituents which are uniformly distributed in the whole alloy. Electrochemical studies indicate that HSSP has 439 ± 20 and 359 ± 2 mV of overpotential (η) at current density of 10 mA cm−2 initially and after 50 h study of OER in 1 M KOH. This initial and 50 h study of η is comparatively higher than the benchmark RuO2 catalyst under identical measurement. This study reveals that HSSP acts as a pre-electrocatalyst due to the presence of electrocatalytically active minor constituents of Cr, Mo, W and V with major content of Fe. It can be considered as a possible alternative to the high cost and precious RuO2 catalyst for OER and can also be utilized in other catalytic applications in alkaline medium.