Understanding the hematite nanostructured surface performing water adsorption microcalorimetry

• Grant number: 16/02157-2
• Support Opportunities: Scholarships abroad - Research
• Start date: August 14, 2016
• End date: August 13, 2017
• Field of knowledge: Physical Sciences and Mathematics - Physics - Condensed Matter Physics
• Principal Investigator: Flavio Leandro de Souza
• Grantee: Flavio Leandro de Souza
• Host Investigator: Ricardo Hauch Ribeiro de Castro
• Host Institution: Centro de Ciências Naturais e Humanas (CCNH). Universidade Federal do ABC (UFABC). Santo André , SP, Brazil
• Institution abroad: University of California, Davis (UC Davis), United States

Abstract

Hematite is the fourth element in abundance in Earth and most stable allotropic phase of iron. In the recent years intensive investigation has been done due hematite potential application as photoanode in photoelectrochemical cells (PEC) for the hydrogen generation through the water molecule splitting reaction assisted by sunlight. Despite innumerous progresses to make hematite as a commercial material for PEC application, many challenges still need to be overcome. In this sense, undoped and doped (Sn, W, and Ti) hematite will be synthesized by aqueous solution route under hydrothermal conditions at low temperature (at 100 oC) and short time (1 h). For obtaining the desired phase and activate the sample surface, additional thermal treatment at 750 oC is needed. Since it is a consensus that the use of additional thermal treatment at high temperature is mandatory for reaching a good photoelectrocatalytic performance from hematite a truly understanding of temperature effect is still a challenge. The main focus of this research proposal is to investigate and understand the role of temperature of thermal treatment on hematite surface activation using calorimetric methods at (room temperature or high temperature). In addition, the use of dopants and different crystal face will also be investigated to elucidate their effect on charge transport and chemical reactions at the surface. Several techniques will be additionally carried out in combination with water adsorption microcalorimetry such as, X-ray diffraction, High temperature oxide melt drop solution calorimetry and thermogravimetric technique, scanning and transmission electron microscopy coupled with chemical analysis to elucidate the sample composition. These findings will provide a deeper understanding of the fundamental characteristics and limitations of hematite to help us making it suitable materials for application as photoanode in PEC devices. (AU)

Scientific publications

(4)

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

SOUZA, FLAVIO L.. Sunlight-driven water splitting using hematite nanorod photoelectrodes. Anais da Academia Brasileira de Ciências, v. 90, n. 1, 1, p. 745-762, 2018. (11/19924-2, 16/02157-2, 13/07296-2)

CARVALHO-JR, W. M.; MENDONCA-FERREIRA, L.; COSTA, F. N.; FERREIRA, F. F.; MUCHE, D. N. F.; TOFANELLO, R. A.; CASTRO, R. H. R.; SOUZA, F. L.. Annealing control of hydrothermally grown hematite nanorods: Implication of structural changes and Cl concentration on weak ferromagnetism. Journal of Alloys and Compounds, v. 799, p. 83-88, AUG 30 2019. (16/02157-2, 13/05471-1, 13/07296-2, 11/19924-2)

ITO, NATHALIE MINKO; CARVALHO, JR., WALDEMIR MOURA; MUCHE, DERECK NILLS FERREIRA; CASTRO, RICARDO HAUCH RIBEIRO; DALPIAN, GUSTAVO MARTINI; SOUZA, FLAVIO LEANDRO. High temperature activation of hematite nanorods for sunlight driven water oxidation reaction. Physical Chemistry Chemical Physics, v. 19, n. 36, p. 25025-25032, SEP 28 2017. (13/05471-1, 11/19924-2, 16/02157-2, 13/07296-2)

MUCHE, DERECK N. F.; SOUZA, FLAVIO L.; CASTRO, RICARDO H. R.. New ultrasonic assisted co-precipitation for high surface area oxide based nanostructured materials. REACTION CHEMISTRY & ENGINEERING, v. 3, n. 3, p. 244-250, JUN 1 2018. (16/02157-2)