Experimental investigation and performance evaluation of an improved alkaline water electrolysis for hydrogen production

Abstract

A potential approach to advancing clean hydrogen energy is the development of cost-effective and durable electrode systems with improved catalytic activity and optimized electrolyser designs. In this study, a compact, membrane-free concentric cylindrical electrolyser is developed to investigate the combined effects of electrode geometry and surface modification on hydrogen evolution behavior. In this regard, the stainless-steel electrodes are coated with nickel (Ni), copper (Cu), and iron (Fe) via electrodeposition and experimentally evaluated at different potassium hydroxide (KOH) concentrations (0.5, 1, and 2 M), applied voltages (2, 3, and 4 V), and electrode surface areas (80-330 cm 2 ). The present results demonstrate that hydrogen production is strongly influenced by the coating material, electrode surface area, and operating conditions within the investigated cylindrical configuration. Among the tested electrodes, the Ni-coated electrode exhibits the highest hydrogen production rate (45.09 mg H 2 h −1 at 3 V and 1 M KOH), followed by the Cu-coated (42.32 mg H 2 h −1 ) and Fe-coated (38.22 mg H 2 h −1 ) electrodes. The corresponding specific energy consumption (SEC) values are found to be 7.17, 7.67, 8.48, and 15.34 kWh Nm −3 H 2 for the Ni-coated, Cu-coated, Fe-coated, and bare stainless-steel electrodes, respectively. The Ni-coated stainless-steel electrode exhibits the highest energy and exergy efficiencies among the investigated electrode configurations, achieving energy and exergy efficiencies of 41.8% and 40.6%, respectively. Overall, this study demonstrates the feasibility of integrating electrodeposited metallic coatings with a membrane-free concentric cylindrical configuration as a laboratory-scale proof-of-concept approach for alkaline water electrolysis.