Dissolution of constituent elements from various austenitic stainless steel oxygen evolution electrodes under potential cycle loadings. (8th September 2022)

• Record Type: Journal Article
• Authors: Todoroki, Naoto; Wadayama, Toshimasa
• Is Part Of: International journal of hydrogen energy. Volume 47:Number 77(2022)
• Page Start: 32753
• Page End: 32762
• Publication Date: 2022-09-08
• Subjects: Stainless steel -- Corrosion -- Oxygen evolution reaction -- Alkaline water electrolysis -- Potential fluctuation; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2022.07.175
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: We investigated the dissolution behaviors of major constituent elements (Fe, Cr, Mn, and Ni) and minor elements (Mo, Ti, and Nb) from austenitic stainless steel (SS) oxygen evolution electrodes for alkaline water electrolyzers (AWE) under potential cycle (PC) loadings. SS substrates of 301, 304, 310S, 316, 321, and 347 grades were used as the starting electrodes. Considering the potential fluctuation environments of AWE, PCs between 0.5 and 1.8 V vs. reversible hydrogen electrode were loaded for the SS electrodes in 7 mol L −1 KOH. After applying the 20, 000 PCs, the amounts of each dissolved constituent element increased in the order of Fe, Cr, Mn, and Ni irrespective of the SS grades. In particular, the dissolutions of Fe and Cr were suppressed, with decreasing Fe/Ni ratios of the starting SS substrate, and they were the smallest in SS310S. Surface cross-sectional observations conducted by scanning electron microscopy with energy-dispersive X-ray spectroscopy indicated that such a dependence of the dissolution on the constituent elements can be explained by the difference in microstructure of the surface (hydro)oxides generated by the application of PCs. The results suggest that the Fe/Ni ratio of the starting SS electrodes is one of the key parameters that determine the dissolution behavior of the elements, that is, its corrosion resistance against the potential fluctuations in austenitic SS-made oxygen evolution electrodes. Graphical abstract: Image 1 Highlights: Corrosion of austenitic stainless steel electrodes for alkaline water electrolyzer was investigated. Potential cycles between 0.5 and 1.8 V vs. reversible hydrogen electrode were loaded. Dissolution of Fe and Cr was suppressed with a decrease in the Fe/Ni ratios of the SS substrate. The total dissolution amount was the lowest for the 310S electrode.