Hydrogen production from hydrogen sulfide via a uniquely designed electrolysis process: experimental investigation

• The Fe-Cl hybrid process is experimentally validated for H 2 production from H 2 S. • H 2 production is tested using FeCl 3 and KOH electrolytes (20–80 °C). • EIS is used under potentiostatic and galvanostatic modes for cell characterization. • H 2 production increased by 426 % with temperature rise from 20–80 °C. • EIS results show reduced impedance and improved charge transfer efficiency. The present work aims to develop a uniquely designed experimental test rig for hydrogen (H 2 ) production from hydrogen sulfide (H 2 S) and perform performance tests. The experimental activity focuses on the FeCl 3 hybrid process for H 2 S cracking, followed by H 2 S absorption, sulfur purification, and electrolysis for efficient H 2 production. Hydrogen production is studied using KOH and FeCl 3 electrolytes under varying temperatures between 20-80 °C. An electrochemical impedance spectroscopy (EIS) is employed to characterize the electrochemical cell under potentiostatic (0.5-2.0 V) and galvanostatic (0-0.5 mA) modes to analyze the system’s electrochemical response. The study results showed that hydrogen production increased by over 426 % from 20 °C to 80 °C. EIS analysis under potentiostatic mode showed Nyquist semicircle diameter reduced as the applied voltage increased from 0.5 V to 1.5 V, and phase angle shifted from -5.59° to -1.27°, confirming enhanced conductivity. Under galvanostatic mode, the impedance dropped from ∼25 Ω to ∼21 Ω as current increased, demonstrating improved kinetics for efficient H 2 production.