High temperature activation of hematite nanorods for sunlight driven water oxidation reaction

Author(s)

Ito, Nathalie Minko ^[1] ; Carvalho, Jr., Waldemir Moura ^[1] ; Muche, Dereck Nills Ferreira ^{[2, 3]} ; Castro, Ricardo Hauch Ribeiro ^{[2, 3]} ; Dalpian, Gustavo Martini ^[1] ; Souza, Flavio Leandro ^{[2, 3, 1]}

Affiliation

^[1] Univ Fed ABC, CCNH, Av Estados 5001, BR-09210580 Santo Andre, SP - Brazil

^[2] Univ Calif Davis, Dept Mat Sci & Engn, One Shields Ave, Davis, CA 95616 - USA

^[3] Univ Calif Davis, NEAT ORU, One Shields Ave, Davis, CA 95616 - USA

• Document type: Journal article
• Source: Physical Chemistry Chemical Physics; v. 19, n. 36, p. 25025-25032, SEP 28 2017.
• Web of Science Citations: 6

Abstract

Here we show that chlorine species originating from commonly used iron precursors annihilate the hematite nanorod photocurrent by providing recombination pathways. Although hematite nanorod films could be obtained by thermal decomposition of the iron oxyhydroxide phase (beta-FeOOH), indistinguishable photocurrent responses under dark and sunlight irradiation conditions were observed until the nanorods were annealed (activated) at 750 degrees C. The annealing led to the elimination of observable chlorine species and allowed photocurrent responses of 1.3 mA cm(-2) at 1.23 V vs. RHE, which is comparable to the best results found in the literature, suggesting that residual chlorine species from the synthesis can act as electron traps and recombination sites for photogenerated holes. (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 Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 11/19924-2 - Study and development of advanced novel materials: electronic, magnetic and nanostructured: an interdisciplinary approach
• Grantee: Carlos Rettori
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 16/02157-2 - Understanding the hematite nanostructured surface performing water adsorption microcalorimetry
• Grantee: Flavio Leandro de Souza
• Support Opportunities: Scholarships abroad - Research
• FAPESP's process: 13/07296-2 - CDMF - Center for the Development of Functional Materials
• Grantee: Elson Longo da Silva
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC