Photoelectrochemical Hydrogen Production from Aqueous Solution Containing Cyanide Using Bi₂MNbO₇ (M = Al, Fe, Ga, In) Films on Stainless Steel as Photoanodes

Photoelectrochemical water splitting (UV–Vis, 2.5 V) from alkaline solution containing cyanide was evaluated in a conventional two-compartment electrochemical cell by using Bi₂MNbO₇ (M = Al, Fe, Ga, In) films on AISI/SAE 304 stainless steel as photoanode and a silver plate as cathode. The films were prepared by sol–gel dip-coating followed by a thermal treatment at 500 °C. They were characterized by scanning electron microscopy, X-ray diffraction and energy dispersive X-ray fluorescence. During the photoelectrochemical process, both circulating current and hydrogen production were measured. Changes in cyanide concentration were determined by potentiometric titration. The activity of Bi₂MNbO₇ films was higher or equivalent than that of TiO₂ film and dependent on the electrolyte composition and concentration. The obtained results make further work on the subject very encouraging.