a-Fe2O3/g-C3N4 Heterostructures: Preparation, Characterization and Gas-sensing Properties

• Grant number: 18/18208-0
• Support type: Scholarships in Brazil - Post-Doctorate
• Effective date (Start): October 01, 2019
• Effective date (End): September 30, 2022
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Nonmetallic Materials
• Principal researcher: Elson Longo da Silva
• Grantee: Ariadne Cristina Catto
• Home Institution: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil
• Associated research grant: 13/07296-2 - CDMF - Center for the Development of Functional Materials, AP.CEPID

Abstract

Nowadays, in order to control the presence of toxic gases in the urban areas, there is a need for sensitive and stable electronic sensors suited for detection from low ppb level to environmental monitoring and warfare agent detection. Among the materials for gas sensing, iron oxide (a-Fe2O3) and carbon nitride (g-C3N4) have revealed promising. However, the high operating temperatures (150 a 500oC) of these sensors make hindering their practical applications. Recent studies have shown that the junction between two semiconductors contributes significantly to the active site numbers available enhancing the gas sensing properties of such materials. Additionally, the formation of the heterojunction has also been shown to be beneficial for reduction of the working temperatures of the sensor materials. We propose herein the synthesis of the a-Fe2O3 and g-C3N4 nanostructures and the a-Fe2O3/g-C3N4 heterojunctions for investigation as resistive gas sensor. The heterostructures will be produced via sonochemical methods from the preformed compounds, and the a-Fe2O3, and g-C3N4 compounds will be synthesized via nonaqueous Sol-gel route, and thermal polymerization, enabling a controlled and reproductive preparation of these materials. DC electrical measurements will be performed under oxidizing and reducing gases (e.g. O3, NO2, NH3) for evaluation of the gas sensing performance. Furthermore, we also propose an investigation "in-situ and operando" by using AC impedance spectroscopy to understand the role of different regions of the device (bulk and interfaces) involved in the gas sensing mechanism of the synthesized samples.

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)

CATTO, ARIADNE C.; OLIVEIRA, MARISA C.; RIBEIRO, RENAN A. P.; AVANSI JR, WALDIR; DA SILVA, LUIS F.; LONGO, ELSON. Hematite rhombuses for chemiresitive ozone sensors: Experimental and theoretical approaches. Applied Surface Science, v. 563, OCT 15 2021. Web of Science Citations: 0.

MIRABELLA, D. A.; DESIMONE, P. M.; PONCE, M. A.; ALDAO, C. M.; DA SILVA, L. F.; CATTO, A. C.; LONGO, E. Effects of donor density on power-law response in tin dioxide gas sensors. SENSORS AND ACTUATORS B-CHEMICAL, v. 329, FEB 15 2021. Web of Science Citations: 0.

DA SILVA, LUIS F.; CATTO, ARIADNE C.; BERNARDINI, SANDRINE; FIORIDO, TOMAS; DE PALMA, JOAO V. N.; AVANSI, JR., WALDIR; AGUIR, KHALIFA; BENDAHAN, MARC. BTEX gas sensor based on hematite microrhombuses. SENSORS AND ACTUATORS B-CHEMICAL, v. 326, JAN 1 2021. Web of Science Citations: 0.

CATTO, ARIADNE C.; FERRER, MATEUS M.; LOPES, OSMANDO F.; MASTELARO, VALMOR R.; ANDRES, JUAN; DA SILVA, LUIS F.; LONGO, ELSON; AVANSI JR, WALDIR. The role of counter-ions in crystal morphology, surface structure and photocatalytic activity of ZnO crystals grown onto a substrate. Applied Surface Science, v. 529, NOV 1 2020. Web of Science Citations: 0.