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

Abstract

Photoelectrochemical water splitting (UV-Vis, 2.5 V) from alkaline solution containing cyanide was evaluated in a conventional two-compartment electrochemical cell by using Bi 2 MNbO 7 (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 Bi 2 MNbO 7 films was higher or equivalent than that of TiO 2 film and dependent on the electrolyte composition and concentration. The obtained results make further work on the subject very encouraging.

Photoelectrochemical Performance of S,N-Codoped TiO2 Films Supported on Ti and their Enhanced Photoelectrocatalytic Activity in the Generation of Hydroxyl Radicals

“…1, FESEM micrographs of TiO 2 /Ti electrode depict a cracked surface attributed to contraction of the film during thermal treatment. 51,52 However, Ti support is not exposed because four layers of TiO 2 were deposited. Its EDS spectrum shows the same peaks as that of uncoated Ti support.…”

The History and Prospective of the AOPs for Environmental Applications in Colombia**

“…Nowadays, the research on AOPs in Colombia is focused on the treatment of contaminated water with coupled systems between AOPs or biological processes [36–43] . The first report of a coupled system belongs to the GDCON group (Universidad de Antioquia, 2008).…”

“…[35] Nowadays, the research on AOPs in Colombia is focused on the treatment of contaminated water with coupled systems between AOPs or biological processes. [36][37][38][39][40][41][42][43] The first report of a coupled system belongs to the GDCON group (Universidad de Antioquia, 2008). They published two studies where the degradation of BPA was evaluated by applying two combined systems: photocatalysis/ultrasound (PÀ U) and photo-Fenton/ ultrasound (PFÀ U).…”

Mixed oxide semiconductors based on bismuth for photoelectrochemical applications

“…They were prepared as powders initially by solid-state reaction [29][30][31][32] and then by the sol-gel method [35] and metalorganic decomposition processes [36]. In our research groups, we have prepared a series of mixed oxide semiconductor films of the Bi-Nb-M-O system (M = Al, Fe, Ga, In) which have presented good physical, optical, photocatalytic, and photoelectrocatalytic properties [37][38][39][40]. However, the films in fact consist of a mixture of mixed oxides, which had not been identified so far, so it is not possible to define a correct structure for this material.…”

“…Despite all the above, the films exhibit visible light absorption properties and presented good photocatalytic activity in the oxidation of methyl orange [37,38]. Additionally, these mixed oxide films were used as photoanodes in the photoelectrochemical hydrogen production from alkaline solutions containing cyanide showing a marked increase in their activities compared with the analogous electrochemical process (in the dark) [39,40]. Nevertheless, the obtained results cannot be straightforward correlated with the optical or structural properties of the films, and apparently the photoelectrochemical properties have a major contribution in this behavior.…”