Assessment of hydrogen production using NaOH and KOH alkaline with different plates and concentrations: An experimental approach
Khaled Ramzy, W.A. El-Askary
Abstract
Alkaline water electrolysis is a pivotal technology for sustainable hydrogen generation. While the individual effects of operational parameters are well-documented, a significant research gap exists in understanding the synergistic interaction between electrolyte chemistry and electrolyzer structural design. This study addresses this gap by presenting a holistic experimental investigation into the coupled effects of electrolyte type (NaOH, KOH), concentration (5–20 %), and electrode plate count (4, 6, 8) on hydrogen production rate, thermal stability, and system efficiency. Three distinct electrolyzer prototypes-varying in material, complexity, and cost were constructed and tested under identical conditions with a 12 V, 30 A DC supply. The results demonstrate that higher electrolyte concentrations (15–20 %) significantly enhance ionic conductivity and hydrogen yield, with KOH exhibiting marginally superior performance due to its higher conductivity. Crucially, the number of electrode plates non-linearly impacts performance; while increasing plates generally improves hydrogen production and thermal management, an optimal configuration of 6 plates was identified, beyond which factors like bubble resistance and uneven current distribution diminish returns. Model 3, with its optimized polyethylene design and 8-plate setup, achieved the highest efficiency and operational stability but at a higher fabrication cost. The novel finding of this work is the identification of a critical trade-off: systems with low concentrations (5 %) exhibit rapid temperature rise despite theoretical conductivity advantages, highlighting a previously underexplored thermal sensitivity. This study provides actionable insights into the integrated optimization of electrolyte properties and reactor geometry, offering a practical framework for designing cost-effective, efficient, and durable alkaline water electrolyzers for scalable hydrogen production.