Theoretical and experimental investigation of Ag and Pt-decorated In2O3 gas sensors: the role of oxygen vacancies

• Grant number: 25/23707-0
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Start date: April 15, 2026
• End date: April 14, 2027
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Nonmetallic Materials
• Principal Investigator: Diogo Paschoalini Volanti
• Grantee: Gustavo Sanghikian Marques dos Santos
• Supervisor: Juan Manoel Andres Bort
• Host Institution: Instituto de Biociências, Letras e Ciências Exatas (IBILCE). Universidade Estadual Paulista (UNESP). Campus de São José do Rio Preto. São José do Rio Preto , SP, Brazil
• Institution abroad: Universitat Jaume I, Spain
• Associated to the scholarship: 24/03388-4 - Influence of electronic and structural defects on In2O3-based sensors decorated with noble metals for detection of microbial volatile organic compounds, BP.DR

Abstract

Environmental safety from hazardous gases is essential for human health protection, requiring materials capable of fast and selective detection. Semiconductor metal oxides stand out for gas sensing due to their favorable chemical and electrical properties. This proposal aims to simulate, synthesize, and characterize In2O3-based sensors, which have been modified through the deposition of noble metals (Ag and Pt) and femtosecond laser irradiation, for the detection of microbial volatile organic compounds (mVOCs). The noble metal decoration changes the oxygen vacancy concentration of the material and directly influences its sensing properties. These simulations are crucial for investigating sensing mechanisms and the role of oxygen vacancies. Density functional theory (DFT) calculations will be employed to investigate the structural, electronic, and energetic properties, including band structure, density of states, vacancy stability, and the electronic effects induced by laser irradiation. Adsorption mechanisms of key mVOCs (e.g., 2-butanone, ethyl acetate, 3-methyl-1-butanol, 1-pentanol, and 1-butanol) will be investigated using the adsorption energies. Experimentally, the sensors will be synthesized and subjected to femtosecond laser irradiation, which changes the number of defects, enabling a tunable gas-sensing material due to the conductivity increase and an enhanced adsorption of mVOC. By integrating theoretical simulations with experimental validation, this work aims to develop high-performance Ag-In2O3 and Pt-In2O3 sensors and to investigate the role of oxygen vacancies in enhancing mVOC detection. This combination of theoretical and experimental approaches is barely studied regarding mVOC sensors, enabling the development of reliable point-of-care devices for early monitoring. (AU)