Hydrogen Evolution Reaction in an Alkaline Solution via e-Fe_3N Phase Formation on AISI 316 Stainless Steel by Plasma Treatment

摘要

Surface modification techniques can be used to enhance the use of low-cost materials in water electrolysis applications, improving their hydrogen evolution efficiency and life. In this work, a well-known AISI 316 stainless steel was treated with nitrogen direct current glow discharge plasma for the periods of 2, 3, 4, and 5 hours. The ε-Fe_3N phase was created from the first plasma treatment period, as detected by the X-ray powder diffraction and X-ray photo-electron spectroscopy investigations. To understand the effect of the ε-Fe_3N phase formation and growth on the hydrogen evolution rate and mechanism both the electrochemical and electro-chemical impedance spectroscopy measurements were done. Advanced plasma treatment over time and enhanced ε-Fe_3N phase growth were found to decrease the Tafel slope, over-potential, and polarization resistance, which contributes to improving the hydrogen evolution reaction properties of AISI 316 stainless steel. A lab scale electrolyzer equipped with a distilled water displacement attachment was prepared to evaluate the HER practically. The contact angle was measured to find an evidence on the effect of the advanced plasma treatment on the surface hydrophilicity.