This study reports the hydrogen production using TiO2 based composite polybenzimidazole membranes through the SO2 depolarized electrolysis that requires lower energy input than the direct water electrolysis. Composite membranes prepared and studied in this work showed very promising results in terms of proton conductivity, chemical stability, and crossover. Thus, a reduction in SO2 crossover was observed with the increase of the concentration of TiO2, obtaining reductions as high as 42% with the 3.0 wt% TiO2-PBI membrane at 120 °C. Higher hydrogen production rates and Faradaic efficiencies were achieved by all the composite membranes, with an optimum for the 1.0 wt% TiO2-PBI membrane (with this membrane, the production of hydrogen increased a 53% at 110 °C and a 49% at 120 °C as compared with the standard PBI membrane), demonstrated the benefit of the use of composite membranes with respect to the standard one for green hydrogen production.
Keywords: SO2 crossover; SO2 depolarized electrolysis; TiO2; chemical stability; composite membrane; green hydrogen; high-temperature electrolysis; polybenzimidazole; proton conductivity.