Influence of Water Source and Electrolyte pH on Hydrogen Production Efficiency in Laboratory-Scale PEM Electrolysis

Abstract

Hydrogen production via water electrolysis represents a scalable and zero-emission pathway for sustainable energy applications. This study evaluates the effects of water source and electrolyte pH on hydrogen generation efficiency using a membrane-based electrolysis system integrating Proton Exchange Membrane (PEM) and Membrane-Based Reactor (MBR) technologies. In the first condition, untreated normal tap water and deionized (DI) water were compared under identical operational parameters. Results indicate that tap water achieved a superior hydrogen production rate of 0.1443 L/min, exceeding the 0.1354 L/min obtained with DI water, attributed to the enhanced ionic conductivity of tap water. In the second condition, the influence of electrolyte pH was examined exclusively using tap water across a pH range of 5 to 10. Peak hydrogen production was recorded at pH 6, corresponding to an optimal balance of proton availability, ionic mobility, and electrode stability, with an output of 0.1443 L/min. Deviations toward strongly acidic (pH 5) or alkaline conditions (pH ? 8) resulted in reduced hydrogen evolution rates due to increased overpotentials, elevated system resistance, and gas bubble accumulation. These findings underscore the electrochemical advantages of moderate ionic content in water sources and the critical role of pH regulation in maximizing hydrogen production efficiency for decentralized electrolysis systems.