Figure 3
From: Hydrogen evolution reaction measurements of dealloyed porous NiCu
SEM images of NiCu films before (a, c, e) and after (b, d, f) the dealloying procedure. The initial copper content in the films are (a) 9.0±0.5%, (c) 12.6±0.6%, and (e) 21.4±1.1%. The copper content in the dealloyed films are (b) 9.5±0.5%, (d) 11.4±0.6%, and (f) 13.9±0.7%. The scale bar is 5 μ m for all the images.