Stainless steel as gas evolving electrodes in water electrolysis: Boosting the electrocatalytic hydrogen evolution reaction on electrodeposited Ni@CoP modified stainless steel electrodes

Abstract

High efficient and durable electrocatalytic electrodes play a vital role in energy conversion and storage. In this concern, water electrolysis technology needs high performance electrodes with high activity and stability to implement this technology for green hydrogen production. Here, this study reports on the development of self-supported electrodes for the hydrogen evolution reaction (HER) based on sequential electrodeposition technique. First, the CoP has been deposited on stainless steel mesh (SSM) electrode followed by deposition of Ni to form Ni@CoP electrocatalysts standing on SSM. The loading amount of Ni was studied to achieve a high catalytic activity. The developed electrodes have been investigated with FE-SEM, EDX, XRD and XPS to identify their morphological properties as well as their chemical states and compositions. Electrocatalytic activity and durability have been studied in alkaline media by different electrochemical methods, such as LSV, EIS and CP. The results showed that the optimum deposition time of 10 min (10Ni@CoP) exhibited the higher catalytic activity in term of overpotential and Tafel slope giving a overpotential of 188 mV at 10 mA cm−2 with a small Tafel slope of 69 mV.dec−1 compared to CoP electrode with overpotential 266 mV and Tafel slope of 105 mV.dec−1 highlighting the role of Ni in enhancing the catalytic activity of the developed electrodes towards HER. Moreover, the Ni@CoP showed high stability under continues electrolysis at 50 and 100 mA.cm−2. These findings have been discussed in light of porous structure of the electrodes and introducing of Ni particles which led to creating more active sites and enhancing the hydrogen adsorption/desorption and thus facilitating the HER kinetics. The facial preparation method of self-supported electrodes and the obtained activity and stability of Ni@CoP electrodes render them as potent electrodes for HER in alkaline water electrolysis.