Metal Doping to Enhance the Photoelectrochemical Behavior of LaFeO3Photocathodes.
The development of tandem devices for water photosplitting requires the preparation of photocathodic materials based on earth-abundant elements that show long-term stability in aqueous electrolytes. Ternary metal oxides seem to be a viable option, among which perovskites stand out. In this context, transparent and compact LaFeO3thin-film electrodes have been prepared by a sol-gel process, both undoped and doped with metals (M) such as Mg or Zn. Pristine electrodes support the development of cathodic photocurrents in 0.1 m NaOH aqueous solutions, particularly in the presence of oxygen, with an onset potential as high as 1.4 V versus the reversible hydrogen electrode. Doping with Mg or Zn leads to an important enhancement of the photocurrent, which peaks for a stoichiometry of LaFe0.95M0.05O3with a sixfold enhancement with respect to the pristine material. Such an improvement is attributed to an increase in both the density and mobility of the majority carriers, although a contribution of surface passivation cannot be excluded.
Departament de Química Física i Institut Universitari d'Electroquímica, Universitat d'Alacant, Apartat 99, E-, 03080, Alicante, Spain.
María Isabel
MI
Díez-García
Departament de Química Física i Institut Universitari d'Electroquímica, Universitat d'Alacant, Apartat 99, E-, 03080, Alicante, Spain.
Roberto
0000-0002-5231-8032
R
Gómez
D004563:Electrochemistry; D004566:Electrodes; D008274:Magnesium; D008670:Metals / Q000737:chemistry*; D010087:Oxides; D010777:Photochemistry; D010782:Photolysis; D014867:Water / Q000737:chemistry; D015032:Zinc
D008670:Metals; D010087:Oxides; C518665:lanthanum iron oxide; D014867:Water; D008274:Magnesium; D015032:Zinc
doping; lanthanum; perovskite phases; photochemistry; water splitting