Stainless steel as gas evolving electrodes in water electrolysis: Enhancing the activity for hydrogen evolution reaction via electrodeposition of Co and CoP catalysts

A facile electrodeposition strategy has been used to modify the stainless steel mesh with Co and CoP catalysts (Co-SSM and CoP-SSM) to be utilized as free-standing electrodes for hydrogen evolution reaction (HER) in alkaline media. The electrodeposition parameters have been optimized to achieve the high catalytic activity. The surface morphologies, the crystal phases and compositions have been identified by SEM, XRD and XPS analyses. The XRD results showed that the Co catalyst (Co-SSM) is present in two mixtures of hexagonal and cubic metallic phases, while the incorporation of P into Co in CoP-SSM resulted in the creation of an amorphous phase as detected by XRD and confirmed from XPS. The CoP-SSM electrode exhibited high electrocatalytic activity towards HER with an overpotential of 264 mV vs. RHE compared to 382 mV and 462 mV for Co-SSM and the pristine SSM electrodes; respectively. Moreover, the CoP-SSM electrode exhibited high stability after continues electrolysis at 50 mA cm −2 with only potential increase of 42 mV after 20 h. These results introduce the developed CoP-SSM electrodes as highly active and stable electrodes for the application in alkaline water electrolysis technology for hydrogen production.