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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.)

All-electrochemically synthesized tin and nickel oxide-modified hematite as photo-electrocatalyst anodes for solar-driven water splitting

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Author(s):
Silva, Anelisse B. [1] ; da Silva, Camila D. F. [1] ; Souza, Flavio L. [2, 3] ; Lucas, Francisco W. S. [1] ; Lima, Fabio H. B. [1]
Total Authors: 5
Affiliation:
[1] Univ Sao Paulo, Inst Chem Sao Carlos, Trabalhador Sao Carlense Av 400, BR-13560970 Sao Carlos, SP - Brazil
[2] Univ Fed ABC, Ctr Ciencias Nat & Humanas, BR-09210170 Santo Andre, SP - Brazil
[3] Brazilian Ctr Res Energy & Mat CNPEM, Brazilian Nanotechnol Natl Lab LNNano, BR-13083970 Campinas, SP - Brazil
Total Affiliations: 3
Document type: Journal article
Source: JOURNAL OF CATALYSIS; v. 391, p. 273-281, NOV 2020.
Web of Science Citations: 2
Abstract

Sn- and NiOx-modified Fe2O3 (hematite) films were entirely synthesized via electrodeposition procedure, followed by thermal treatment, and tested as photo-electrocatalyst for water splitting, in alkaline electrolyte. The optimization of the Sn and NiOx electrodeposition loadings on Fe2O3 produced a maximum photocurrent density of 1.35 mA cm(-2) at 1.23 V (vs. RHE), with the highest shift on the reaction onset potential, representing a large improvement in relation to bare hematite. Long-term photoelectrolysis studies of the Fe2O3/Sn-10/NiOx at 1.23 V showed that the photocurrent density remained stable for at least 24 h. The assessment of the results from the calculations of charge separation (eta(sep)) and charge injection (eta(cat)) efficiencies revealed an improvement in both parameters, with the addition of tin into hematite. This was ascribed to its beneficial effect on lowering the charge recombination of the photogenerated charge carriers on grain-boundaries and on the hematite/electrolyte interface. Additionally, it was evidenced that NiOx was more important on the increase in the charge injection, since it is a hole collector, acting as co-catalyst, which improves charge transfer rate at the interface with the electrolyte. The outcome of the Mott-Schottky analysis displayed a negative shift of the flat band potentials (E-fb) for both, Sn- and NiOx-modified photo-electrocatalysts, due to the passivation of the surface states, and this was in agreement with the mathematical fitting of the curves obtained via photoelectrochemical impedance spectroscopy (PEIS) measurements. The present findings clearly showed that, by allowing a fine-tuning of the amount of the metal modifiers and with an efficient deposition at functional sites of the hematite, this electrodeposition method is a promising strategy to boost hematite performance as photo-electrocatalyst. (C) 2020 Elsevier Inc. All rights reserved. (AU)

FAPESP's process: 13/16930-7 - Electrocatalysis V: electrocatalytic processes of chemical and electrical energy interconversion
Grantee:Edson Antonio Ticianelli
Support Opportunities: Research Projects - Thematic Grants
FAPESP's process: 19/22183-6 - Electrocatalysis VI: fundamental and applied aspects of emerging and classical problems in electrochemical energy conversion
Grantee:Edson Antonio Ticianelli
Support Opportunities: Research Projects - Thematic Grants
FAPESP's process: 16/13323-0 - Carbon Dioxide and Water Electrochemistry: Application in Energy Conversion and Storage
Grantee:Fabio Henrique Barros de Lima
Support Opportunities: Regular Research Grants