Photoelectrochemical Hydrogen Production Using Co-Ni/TiO₂ Integrated with Aquivion and FUMASEP Membranes in an H-Type Cell

Hydrogen production via photoelectrochemical (PEC) water-splitting offers a sustainable approach to clean energy generation. This study compares two polymer electrolyte membranes, Aquivion and FUMASEP, integrated with a Co–Ni/TiO2 photocatalyst in an H-type PEC reactor using a 1 M KOH electrolyte. Aquivion, with its short side chain perfluorosulfonic acid structure, and FUMASEP, an anion-exchange membrane, were evaluated for their effects on catalyst activity, membrane stability, and hydrogen production efficiency. The Co–Ni/TiO2 photocatalyst, synthesized using hydrothermal and wet-impregnation methods, exhibited a favorable nanoscale distribution and mesoporosity, facilitating efficient charge transfer. Electrochemical impedance spectroscopy indicated that Co–Ni/TiO2-Aquivion had the lowest charge transfer resistance (Rct), outperforming Co–Ni/TiO2–FUMASEP and bare Co–Ni/TiO2. Linear sweep voltammetry revealed the highest photocurrent density for Co–Ni/TiO2-Aquivion at 1.8 V vs RHE, corresponding to superior hydrogen production of 13.8 mL at 120 min. Mechanical testing showed the higher tensile strength and stability of Aquivion under alkaline conditions. Although impedance increases after prolonged use, indicating some membrane degradation, Aquivion demonstrated the best balance of electrochemical performance and durability. This study highlights Aquivion as a promising membrane for enhancing PEC hydrogen production efficiency and longevity.