An experimental investigation to improve the hydrogen production by water photoelectrolysis when cyanin-chloride is used as sensibilizer

This paper deals with an experimental investigation to improve the hydrogen production by water photoelectrolysis. An experimental facility was built: it is mainly constituted by a solar simulator, the photoelectrolytic cell, the electric power supply system and a recirculating and gas sampling hydraulic circuit. Titanium dioxide was chosen as catalyst because of its good photocatalytic efficiency and its high stability to pH variations in watery solutions. Cyanin chloride was tested as sensibilizer: it is a flavonoid, an organic dye, which gives to the watery solution better solar radiation absorption performances. The catalyst and the sensibilizer were deposited on the cathode surface. A sacrificial reducing agent, ethylenediaminetetraacetic acid (EDTA), was also introduced in the solution to reduce the sensibilizer and restore the original conditions. Different radiation power and electrolytic pH conditions were tested in order to verify the proposed arrangements. Results showed a growing in the hydrogen production by the proposed photoelectrolytic arrangements with respect to the performance of a simple electrolysis. Thus, the obtained results showed that this technology has good possibilities of improvement and interesting perspective of future development.

► Catalytic photolysis to improve hydrogen production by water photoelectrolysis.
► Titanium dioxide is a good catalyst but with high band gap energy.
► Cyanin chloride as sensibilizer and EDTA as sacrificial agent were proposed.
► A slightly acid electrolyte and a basic electrolyte were tested.
► Maximum solar-to-hydrogen photolytic conversion for a basic watery solution.