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

Abstract

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.

Appropriate Use of Electrochemical Impedance Spectroscopy in Water Splitting Electrocatalysis

“…A Nyquist plot of stainless steel scrubber (316 L) acquired at an OER overpotential of 300 mV in 1.0 M KOH from our earlier study is given as an example that fits with the simple Randle's cell shown below . The resultant Nyquist plot take a shape of a depressed semi‐circle as shown in Figure .…”

“…To avoid this, several materials have been reported to be catalyzing these half‐cell reactions with relatively lower overpotentials. These include noble and precious metals (Pt, Ir, and Ru) and their oxides, non‐precious metals (Mn, Fe, Co, Ni, Cu, V, Ti, Mo, W, and Re) and their compounds and non‐metallic carbonaceous materials . Due to the cost concerns of utilizing noble and precious metals, non‐precious metals based materials are being investigated intensively for electrocatalytic water splitting in recent days.…”

Transforming Damage into Benefit: Corrosion Engineering Enabled Electrocatalysts for Water Splitting

“…However, the elemental compositions of SS are more complex, generally containing the elements of Fe, Ni, Cr, and Mn, which result in the complicated compositions and abundant controllability for SS‐based electrocatalysts. [ 166–168 ] SS not only has the similar advantages to the aforesaid alloys of high electrical conductivity, porous structure and high specific surface area, but also exhibits remarkable corrosion resistance at harsh conditions. [ 169 ] The corrosion resistance produces the difficulty of achieving efficient electrocatalysts by corrosion engineering, but simultaneously endows SS with high durability for electrocatalysis.…”

A Simple and Scalable Approach To Remarkably Boost the Overall Water Splitting Activity of Stainless Steel Electrocatalysts

“…One of the promising approaches to address the tendency of the catalysts peeling off from the substrates is fabricating self-supporting electrocatalysts. 38 On the race to accomplishing the abovementioned approach, the stainless steel mesh (SSM) especially the 304-, 316-, and AISI 304-type has attracted great attention 38,40−42 not only due to its low cost but also its chemical stability in the alkaline environment. 43−45 SSM has shown impressive performance as an OER electrocatalyst in its pristine form 37,38 and significant performance enhancement upon different facile surface modification or exfoliation methods to improve its surface area.…”