Adsorption of Glucose Molecules on Stainless Steel Enables Ni-Rich Passivation Film

Abstract

Stainless steel (SS) is well known for its remarkable versatility. Besides the importance of passivation film for durability and stability of SS, the composition and morphology of passive surface layer have to be precisely modified to create an alloy that is optimal for specific purposes. Herein, we report on the electrochemical preparation of nickel-enriched passive film which is accomplished by the preferential adsorption of glucose on nickel species among constituents of SS. The presence of nickel-rich surface and the exposure of nickel on the outmost surface layer participating in surface reactions are verified by monitoring redox couple of Ni2+/Ni3+ as well as elemental analyses (TEM-Energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy). Reversible interchange of nickel-rich into iron-rich surface and vice versa is possible by adding or removing glucose. We find that molecules having more than tri-dentate of hydroxy groups (e. g. glycerol) is required for the formation of Ni-rich surface (chelate effect). For diverse applications of stainless steel, precise control of the surface layer's composition and morphology is essential. In this work, we study the formation of a nickel-rich passive film via electrochemical potential sweep in an alkaline solution containing glucose. In addition, the nickel- or iron-rich passive surface layer is capable of reversible interchange by adding or removing glucose.image