Stainless Steel Scrubber: A Cost Efficient Catalytic Electrode for Full Water Splitting in Alkaline Medium

Sometimes, searching for a cost efficient bifunctional catalytic material for water splitting can be accomplished from a very unlikely place. In this work, we are reporting such a discovery of utilizing the stainless steel (SS) scrubber directly as a catalytic electrode for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) of water electrolysis in 1 M KOH. The iR corrected overpotential calculated at an areal current density of 10 mA cm^-2 for a SS scrubber in HER is 315 mV which is 273 mV higher than Pt/C. Similarly, the SS scrubber required 418 mV at 10 mA cm^-2 which is just 37 and 98 mV higher than Ni(OH)₂ and RuO₂. Interestingly, the kinetic analysis revealed that the SS scrubber had facile kinetics for both HER and OER in 1 M KOH as reflected by their corresponding Tafel slope values viz., 121 and 63 mV dec^-1, respectively. In addition, the two electrode cell fabricated using the same SS scrubber electrode delivered 10 mA cm^-2 at 1.98 V. Beyond everything, the SS scrubber had shown ultrahigh stability in both half-cell and full-cell studies for total water splitting. Further, as far as the cost of an electrode material per gram is concerned, the SS scrubber defeats all the best electrocatalysts of water splitting by having a price of just $0.012 USD which is $2.228 USD lower than pure Ni, $59.658 USD lower than RuO₂ and $158.028 USD lower than Pt/C 20 wt % catalyst. The overall study specified that the SS scrubber can be adapted for cost-efficient large scale water electrolysis for bulk hydrogen production.