Response surface methodology optimization of NaOH-SLS electrolyte composition for enhanced hydrogen evolution in surfactant assisted alkaline water electrolysis

Alkaline water electrolysis is a key technology for sustainable hydrogen production, but its performance is limited by sluggish hydrogen evolution reaction (HER) kinetics and interfacial transport constraints. This study explores electrolyte engineering using a chloride-free NaOH-sodium lauryl sulfate (SLS) system combined with electrochemical analysis and response surface methodology (RSM). Mixed NaOH-SLS electrolytes outperform single-component systems, indicating synergistic effects between alkalinity and surfactant-induced interfacial modification. RSM identifies an optimal composition that minimizes 10 mA cm⁻² overpotential 𝜂 1 0 , reduces kinetic resistance, and enhances steady-state current density. Experimental validation shows a Tafel slope reduction from 252 to 154 mV dec −1 with improved electrochemical performance. Mechanistic analysis reveals that SLS restructures the electrical double layer, enhances ion transport, and promotes bubble detachment, while excessive loading causes interfacial blocking. These results demonstrate that optimal HER performance depends on balanced hydroxide availability and interfacial organization, establishing electrolyte design as a scalable strategy for improving alkaline electrolysis.