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.