Mixed oxide semiconductors based on bismuth for photoelectrochemical applications

JOSE LUIS ROPERO VEGA; A.M. MELÉNDEZ; J.A. PEDRAZA-AVELLA; ROBERTO J. CANDAL

JOURNAL OF SOLID STATE ELECTROCHEMISTRY (PRINT)

SPRINGER

Lugar: Berlin; Año: 2014 vol. 18 p. 1963 - 1971

1432-8488

The structural and photoelectrochemical propertiesof mixed oxide semiconductor films of Bi-Nb-M-O (M = Al,Fe, Ga, In) were studied in order to explore their use asphotoanodes in photoelectrochemical cells. These films wereprepared on AISI/SAE 304 stainless steel plates by sol?geldip-coating. The films were characterized by scanning elec-tron microscopy?energy dispersive spectroscopy (SEM-EDS), X-ray diffraction (XRD), and X-ray photoelectronspectroscopy (XPS), and their photoelectrochemical proper-ties were studied by open circuit potential (OCP) measure-ments, linear sweep voltammetry (LSV), and cyclic voltamm-etry (CV). SEM micrographs show homogeneous and roughfilms with agglomerates on the surface. EDS analyses showthat the films are composed of Bi, Nb, and M, and theagglomerates aremainly composed of Bi. XRDanalyses showa predominant crystalline phase of bismuth(III) oxide (Bi2O3)and a secondary phase composed of Bi-M mixed oxides. It isnoteworthy that there was no identified niobium-based crys-talline phase. XPS results reveal that the films are composedby Bi(III), Nb(V), and M(III). CV results show that the elec-trochemical behavior is attributed only to the semiconductorfilms which indicate a good coating of the stainless steelsupport. OCP measurements show that all the films have n-type semiconductor properties and exhibited photoresponse tothe visible light irradiation. LSV results show that the appli-cation of a potential higher than +0.1 V enhances the photo-current which can be attributed to an improved charge carrierseparation. The results indicate that these materials can beused in photoelectrochemical cells.