A novel dual-bed photocatalytic water splitting system for hydrogen production

A novel dual-bed system was designed to produce hydrogen through photocatalytic water splitting. The system was comprised of a photocatalytic reaction bed and a regeneration bed. Aqueous KI solution and Pt-loaded TiO₂ constituted the photocatalytic reaction bed where hydrogen was produced; meanwhile the hole scavenger iodide ion was oxidized into I_2. The effluent containing I₂ from the photocatalytic bed entered the regeneration bed and passed through a Cu₂O layer where I₂ was reduced to I⁻. The regeneration bed effluent was then recycled to the photocatalytic reaction bed. Since the hole scavenger KI in the photocatalytic bed was constantly kept at a high level through the continuous reduction of I₂ in the regeneration bed, steady production of hydrogen was achieved in the dual-bed system for a much longer period as compared to a single-bed system without regeneration.