title: Photoelectrochemical Behavior of Electrophoretically Deposited Hematite Thin Films Modified with Ti(IV).
abstract: Doping hematite with different elements is a common strategy to improve the electrocatalytic activity towards the water oxidation reaction, although the exact effect of these external agents is not yet clearly understood. Using a feasible electrophoretic procedure, we prepared modified hematite films by introducing in the deposition solution Ti(IV) butoxide. Photoelectrochemical performances of all the modified electrodes were superior to the unmodified one, with a 4-fold increase in the photocurrent at 0.65 V vs. SCE in 0.1 M NaOH (pH 13.3) for the 5% Ti-modified electrode, which was the best performing electrode. Subsequent functionalization with an iron-based catalyst led, at the same potential, to a photocurrent of ca. 1.5 mA·cm(-2), one of the highest achieved with materials based on solution processing in the absence of precious elements. AFM, XPS, TEM and XANES analyses revealed the formation of different Ti(IV) oxide phases on the hematite surface, that can reduce surface state recombination and enhance hole injection through local surface field effects, as confirmed by electrochemical impedance analysis.
authors.affiliation: Department of Chemical and Pharmaceutical Sciences, University of Ferrara, Via Fossato di Mortara 11-17, 44121 Ferrara, Italy. dllncl@unife.it.
authors.forename: Nicola
authors.initials: N
authors.lastname: Dalle Carbonare
authors.affiliation: Department of Chemical and Pharmaceutical Sciences, University of Ferrara, Via Fossato di Mortara 11-17, 44121 Ferrara, Italy. bar@unife.it.
authors.forename: Rita
authors.initials: R
authors.lastname: Boaretto
authors.affiliation: Department of Chemical and Pharmaceutical Sciences, University of Ferrara, Via Fossato di Mortara 11-17, 44121 Ferrara, Italy. cte@unife.it.
authors.forename: Stefano
authors.initials: S
authors.lastname: Caramori
authors.affiliation: CNR/ISOF c/o Department of Chemical and Pharmaceutical Sciences, University of Ferrara, Via Fossato di Mortara 11-17, 44121 Ferrara, Italy. agr@unife.it.
authors.forename: Roberto
authors.initials: R
authors.lastname: Argazzi
authors.affiliation: Department of Chemical and Pharmaceutical Sciences, University of Ferrara, Via Fossato di Mortara 11-17, 44121 Ferrara, Italy. mau@unife.it.
authors.forename: Maurizio
authors.initials: M
authors.lastname: Dal Colle
authors.affiliation: Department of Physics and Astronomy, University of Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy. luca.pasquini@unibo.it.
authors.forename: Luca
authors.initials: L
authors.lastname: Pasquini
authors.affiliation: Department of Chemical Sciences, University of Padua, Via F. Marzolo 1, 35131 Padua, Italy. renzo.bertoncello@unipd.it.
authors.forename: Renzo
authors.initials: R
authors.lastname: Bertoncello
authors.affiliation: CNR ISTM, Via Fantoli 16/15, 20138 Milan, Italy. m.marelli@istm.cnr.it.
authors.forename: Marcello
authors.initials: M
authors.lastname: Marelli
authors.affiliation: CNR ISTM, Via Fantoli 16/15, 20138 Milan, Italy. claudio.evangelisti@istm.cnr.it.
authors.forename: Claudio
authors.initials: C
authors.lastname: Evangelisti
authors.affiliation: Department of Chemical and Pharmaceutical Sciences, University of Ferrara, Via Fossato di Mortara 11-17, 44121 Ferrara, Italy. g4s@unife.it.
authors.forename: Carlo Alberto
authors.initials: CA
authors.lastname: Bignozzi
mesh_terms: D017097:Electric Impedance; D004563:Electrochemistry; D004566:Electrodes; D005290:Ferric Compounds / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D055668:Photochemical Processes; D010777:Photochemistry; D013057:Spectrum Analysis / Q000379:methods; D014025:Titanium / Q000737:chemistry*
chemical_list: D005290:Ferric Compounds; C000499:ferric oxide; D014025:Titanium
keywords: EIS; doping; electrophoresis; hematite; passivation; titanium; water splitting