Study of Conduction Mechanisms and Interface Defects in CeO2 matrices decorated with nickel oxide and tungsten oxide

• Grant number: 24/04292-0
• Support Opportunities: Research Grants - Visiting Researcher Grant - International
• Start date: June 25, 2024
• End date: July 08, 2024
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Physical-Chemistry
• Principal Investigator: Elson Longo da Silva
• Grantee: Elson Longo da Silva
• Visiting researcher: Celso Manuel Aldao
• Visiting researcher institution: Universidad Nacional De Mar Del Plata/Unmdp, Argentina
• Host 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

The purpose of this project is to study electrical and sensor properties based on CeO2 matrices decorated with p-n (CeO2/NiO) and n-n (CeO2/WO3) junctions. New advances are expected compared to the patent developed by our group (BR10201602838 - Brasil) for this matrix, which present a dual response (electro-optical and electrical). In this work, two preferred morphologies for the CeO2 matrix will be evaluated and then the heterostructures will be coupled and studied. The main objective is to obtain a substantially understanding improvement in the quality between the surface of the sensor behavior compared to previous research employing the microwave-assisted solvothermic method. Specifically, the adsorption mechanisms resulting from the different interfaces (p-n and n-n) and morphologies in relation to clusters, surface defects, and conduction mechanisms will be evaluated. The devices will be characterized using the most modern techniques at the atomic, structural, morphological and electrical levels such as XPS, Positron Anquilation Spectroscopy, Impedance Spectroscopy, among others. The performance of the sensors will be evaluated in atmospheres of oxidizing and reducing gases in sensor chamber developed and patented by the group (PI20150103953 - Argentina). The challenge of this work will be to construct sensors with a designer that allows to study simultaneously the relation of energy and surface defects with the type of junction, factors that in the literature, are still not explored, and has direct relation with sensitivity, shorter response time and working temperature of the sensor device. In this sense experimental results will be correlated to theoretical studies and will enable a deep understanding between structure and property (AU)