Novel integrated electrochemical system for Co-Generation of green hydrogen and hypochlorite: Modeling, optimization, and machine learning insights

• Electrolysis of NaCl brine co-generates ClO⁻ and H₂ using solar power and optimization tools. • Effects of salinity and current density were modeled using RSM and face-centered design. • Optimal output: 1.52 L H₂ and 558 mg L -1 ClO⁻ at 2691.91 mg L -1 NaCl and 75 mA cm - ² current. • ML outperformed RSM with MAE of 8.67 mg L -1 , confirming salinity and current as key factors. This paper investigates an electrochemical system for the co-generation of hypochlorite ions (ClO⁻) and green hydrogen (H 2 ) with synthetic sodium chloride saline solutions using modeling and optimization tools. A hybrid electrolysis setup integrated with a chlorides doser, powered by photovoltaic solar system, was employed to evaluate the effects of NaCl concentrations (1500, 2500, and 3500 mg L -1 ) and current density (25, 50, and 75 mA cm⁻ 2 ) through a face-centered composite design (FCCD) and response surface design (RSM). To enhance predictive accuracy, Machine Learning (ML) approaches were also integrated, and under optimal conditions, 2691.91 mg L -1 NaCl concentration and 75 mA cm⁻² current density, the system produced 1.52 ± 0.16 L of green H 2 and 558.22 ± 11.32 mg L -1 of ClO⁻. High purity of green H 2 and lower level of crossover were confirmed by differential electrochemical mass spectrometry (DEMS). Statistical analysis revealed that salinity and current density as key influential factors, contributing to 46.83% and 30.18%, respectively. Both RSM and ML models exhibited high predictive reliability (R² > 98%), though the latter showed superior precision (MAE: 8.67 mg L -1 vs. 17.39 mg L -1 ). Lastly, a preliminary economic assessment was performed to evaluate both fixed capital investments, primarily associated with the required electrode surface area, and operational expenses, specifically electricity consumption, under optimized conditions.