Electrochemical hydrogen production of SS, Ni and Ni-B electrodes in prototype electrolyzer

Abstract

Highly efficient, low-cost and stable electrocatalysts are crucial in electrocatalytic water splitting. Herein, a comparative study of stainless steel (SS), nickel/stainless steel (Ni/SS) and nickel boride/stainless steel (Ni-B/SS) electrodes for hydrogen production was carried out under a prototype electrolyzer system. Ni/SS and Ni-B/SS were synthesized using a simple and low-cost chemical method on an SS substrate. Compared with the SS and Ni/SS electrodes, the Ni-B/SS electrode demonstrated superior electrochemical activity towards the hydrogen evolution reaction with a low overpotential of 75 mV at a current density of 10 mA/cm2 and a Tafel slope of 82 mV/decade in a 1 M potassium hydroxide (KOH) electrolyte. The as-fabricated Ni-B/SS electrode showed a cauliflower-like morphology and exhibited an excellent hydrogen production rate of 4.39 ml/min on a 2 × 2 cm electrode at a constant potential of 2.2 V in a prototype electrochemical hydrogen production set-up. The stability of the Ni-B/SS (6 × 6 cm) electrode was also checked on a large-scale prototype electrolyzer set-up for 50 h at a constant potential.