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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Thermal enhancement of water affinity on the surface of undoped hematite photoelectrodes

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Carvalho-, Jr., Waldemir M. [1] ; Souza, Flavio L. [1]
Total Authors: 2
[1] Univ Fed ABC, Lab Alternat Energy & Nanomat LEAN, Ctr Ciencias Nat & Humanas, BR-09090400 Santo Andre, SP - Brazil
Total Affiliations: 1
Document type: Journal article
Source: SOLAR ENERGY MATERIALS AND SOLAR CELLS; v. 144, p. 395-404, JAN 2016.
Web of Science Citations: 8

Hematite is one of the most promising semiconductors used to convert solar irradiation directly into chemical energy (molecular hydrogen and oxygen) via water splitting. Although several methods have been developed in the last decades, the repertoire of a method to fabricate hematite electrodes with a large covered area, relative low cost, industrial viability and remarkable properties still remains a challenge. This paper describes a microwave-assisted hydrothermal process to produce hematite films. The photoelectrodes prepared consisted of rods of hematite on the FTO substrate (FTO-fluorine doped tin oxide) forming mesoporous nanostructured. According to the X-ray diffraction data, thin films thermally treated at high temperature grew preferentially to the {[}110] direction, i.e., growth perpendicular to the substrate. Moreover, high temperature of thermal treatment influenced positively on the stability, current density and charge transfer efficiency of photoelectrodes. The impedance spectroscopy (EIS) data aided us to understand the best photoelectrochemical performance exhibited by hematite electrode synthesized during 2 h with additional thermal treatment at 750 degrees C. The high temperature treatments seem to promote higher N-D (charge density) and V-fb values estimated from EIS data, which are related to an efficient photogenerated charge separation (e(-) - h(+)). Additionally, our results suggested that the hematite surface roughness and wettability should be considered as important parameters for producing active electrodes for solar water oxidation. A quasi-super hydrophilic surface observed for electrode sintered at high temperature and illustrated by contact angle images could be favoring solid/liquid interface to increase the surface efficiency for chemical reaction. Finally, this work gives a new insight into the role of high temperatures in the sintering process for the activation of pure hematite photoelectrode surface. (C) 2015 Elsevier B.V. All rights reserved. (AU)

FAPESP's process: 13/05471-1 - Effect of dopants in semiconductor nanostructures and their impact on photocatalytic performance
Grantee:Waldemir Moura de Carvalho Junior
Support type: Scholarships in Brazil - Doctorate
FAPESP's process: 13/07296-2 - CDMF - Center for the Development of Functional Materials
Grantee:Elson Longo da Silva
Support type: Research Grants - Research, Innovation and Dissemination Centers - RIDC
FAPESP's process: 11/19924-2 - Study and development of advanced novel materials: electronic, magnetic and nanostructured: an interdisciplinary approach
Grantee:Carlos Rettori
Support type: Research Projects - Thematic Grants
FAPESP's process: 12/19926-8 - Metal oxide nanostructures applied in photoelectrochemical devices
Grantee:Flavio Leandro de Souza
Support type: Regular Research Grants