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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, 2021
Field of knowledge:Engineering - Materials and Metallurgical Engineering - Nonmetallic Materials
Principal Investigator: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


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.