Hydrogen Evolution Reaction of AC Anodized Stainless Steel 304L

A novel method of anodizing stainless steel (SS) 304L with alternating current (AC) as the power source is presented in order to generate a porous oxide layer. This study aims to investigate the influence of AC anodizing of SS304L on hydrogen evolution reaction (HER) activity and characterize the morphology of oxide film formed. The AC anodization method was carried out using an AC power source in a solution of ammonium fluoride, NH
4
F, water, H
2
O and ethylene glycol at room temperature, with anodizing time ranging from 10 to 50 minutes. Scanning electron microscope (SEM) and a 3D profiler were used to characterize the surface morphology, and a potentiostat is used to study the behaviour of the HER. The results show that the oxide film gradually covered the SS304L surface and fully covered at 30 minutes anodizing time, then begin to crack at 40 and 50 minutes. The thickness of the layer reached its maximum at 5248.67 nm with pore size of 380.13 nm after 30 minutes and then gradually began to decrease. Notably, the lowest HER activity, measuring -426.58 mV, was detected after 30 minutes. These findings clarified the relationship between the AC anodizing time, oxide film morphology, and HER activity, making it easier to optimize stainless steel 304L for enhanced hydrogen evolution applications.