Anodically prepared nanoporous stainless steel electrocatalysts: A self-activated and ultra-stable catalysts for the hydrogen evolution reaction

초록

Stainless steel was well-known as the material which contains the electrocatalytic elements such as Fe, Cr, and Ni, the materials which are distinguished catalysts for hydrogen reduction reaction (2H+ + 2e- → H2). In this study, the performance of anodic nanoporous stainless steel as electrocatalyst for the hydrogen evolution reaction is investigated. Nanoporous stainless steel electrode with large surface area provides a lot of active sites for electrochemical hydrogen evolution reaction. Furthermore, thermal annealing treatment applied to prevents the deterioration of the anodic oxide layer offers ample oxygen vacancies accelerating the reaction kinetics without forming thermal oxide layer under Ar/H2 atmosphere. Remarkably, the overpotential for the hydrogen evolution is additionally reduced from 370 to 348 and 244 mV after linear sweep voltammogram measurement at 10 mA cm-2 for 5000 and 10000 cycles, respectively. The improved catalytic performance along with ultrastability is attributed to the self-activation of stainless steel electrocatalyst ? hydroxylation of the anodic film during repeated cycles. This surface phenomenon is explored by the physical characterizations including x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), and Raman spectroscopy.