Hematite Surface Activation by Chemical Addition of Tin Oxide Layer

Autor(es)

Carvalho, Jr., Waldemir M. ; Souza, Flavio L.

• Tipo de documento: Artigo Científico
• Fonte: ChemPhysChem; v. 17, n. 17, p. 2710-2717, SEP 5 2016.
• Citações Web of Science: 5

Resumo

In this study, the effect of tin (Sn4+) modification on the surface of hematite electrodes synthesized by an aqueous solution route at different times (2, 5, 10, 18, and 24h) is investigated. As confirmed from X-ray diffraction results, the as-synthesized electrode exhibits an oxyhydroxide phase, which is converted into a pure hematite phase after being subjected to additional thermal treatment at 750 degrees C for 30min. The tin-modified hematite electrode is prepared by depositing a solution of Sn4+ precursor on the as-synthesized electrode, followed by thermal treatment under the same abovementioned conditions. This modification results in an enhancement of the photocurrent response for all hematite electrodes investigated and attains the highest values of around 1.62 and 2.3mAcm(-2) at 1.23 and 1.4V versus RHE, respectively, for electrodes obtained in short synthesis times (2h). Contact angle measurements suggest that the deposition of Sn4+ on the hematite electrode provides a more hydrophilic surface, which favors a chemical reaction at the interface between the electrode and electrolyte. This result generates new perspectives for understanding the deposition of Sn4+ on the hematite electrode surface, which is in contrast with several studies previously reported; these studies state that the enhancement in photocurrent density is related to either the induction of an increased donor charge density or shift in the flat-band potential, which favors charge separation. (AU)

• Processo FAPESP: 13/05471-1 - Efeito de dopantes em nanoestruturas semicondutoras e seu impacto no desempenho fotocatalítico
• Beneficiário: Waldemir Moura de Carvalho Junior
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 13/07296-2 - CDMF - Centro de Desenvolvimento de Materiais Funcionais
• Beneficiário: Elson Longo da Silva
• Modalidade de apoio: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs
• Processo FAPESP: 11/19924-2 - Estudo e desenvolvimento de novos materiais avançados: eletrônicos, magnéticos e nanoestruturados: uma abordagem interdisciplinar
• Beneficiário: Carlos Rettori
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 14/50516-6 - Fotossíntese artificial: controle do design dos nanomateriais e fótons promove aumento no desempenho dos dispositivos
• Beneficiário: Flavio Leandro de Souza
• Modalidade de apoio: Auxílio à Pesquisa - Regular