Activation of Commercial Stainless-Steel Electrodes for Highly Efficient and Stable Anion-Exchange Membrane Electrolysis

Abstract

Commercial stainless steel (SS) is gaining interest as a promising electrode material to be widely used for green hydrogen production from alkaline water electrolysis. Herein, low-cost 304-type SS meshes (SM) were engineered through a simple 2-step activation process, i.e., chemical etching and electrochemical activation. The modified electrodes exhibited comparable hydrogen and oxygen evolution reaction properties with commercially, noble metal-based electrodes available. The modified stainless steel-based electrodes were assembled and tested in an AEM electrolyzer cell, which displays more than 300 mV-voltage drops compared to the bare stainless steel-based cells. The in-situ impedance spectroscopy revealed a significant decrease in the resistances due to interfacial contact, charge transfer, and mass transport. In addition, we identified nanocrystalline Fe-NiCr2O4 and nanocrystalline Ni(OH)2/Fe(OH)2 active species for SS used in hydrogen and oxygen evolution side respectively which could explain the significantly higher performance. In addition, we also developed an electrolyzer system to assess the long-term durability of our cell reactors in which our cells exhibited exceptional durability at 5.0 A (1.0 A cm-2) for 250 h. Our results exemplify that such an approach has the potential for upscaling and deployment in the next-generation, low-cost AEM electrolysis for green hydrogen production.