Ethyl Acetate Detection Using Mixed-Phase In₂O₃ Nanorods

Author(s)

dos Santos, Gustavo Sanghikian Marques ; Theodoro, Reinaldo dos Santos ; Gera, Gabriela Oliveira ; Perfecto, Tarcisio Micheli ; Volanti, Diogo Paschoalini

• Document type: Journal article
• Source: ACS APPLIED NANO MATERIALS; v. 8, n. 22, p. 12-pg., 2025-05-08.

Abstract

Detecting microbial volatile organic compounds (MVOCs) is critical for public health and food quality control applications but often requires complex analytical approaches. Ethyl acetate, an MVOC produced during the fermentation of bread and beer by Saccharomyces cerevisiae, holds significance in food quality control. Semiconductor metal oxides, particularly In2O3, are promising materials for MVOC sensing due to their cost-effectiveness, stability, and tunable sensing properties at the nanoscale. Enhanced sensing performance can be achieved by engineering heterostructures combining cubic and rhombohedral phases of In2O3 nanorods. In this work, In2O3 nanorods were synthesized via microwave-assisted hydrothermal method followed by calcination at 600, 500, and 400 degrees C to obtain single-phase cubic (In2O3-600) and mixed-phase cubic-rhombohedral (In2O3-500 and In2O3-400) structures. The In2O3-500 heterostructure nanorods exhibited an enhanced response of 548 to ethyl acetate at 350 degrees C in dry air. It also showed a fast response time (1.8 s), a selectivity ratio of 2.1, and a theoretical detection limit of 525 ppb. Moreover, the material maintained a high response under 90% relative humidity (RH), demonstrating robustness under realistic operating conditions. These findings can be attributed to the synergistic effect of heterojunctions formed between the cubic and rhombohedral phases at the nanoscale, providing numerous active sites and defect-driven reactivity. The post-mortem characterization of the nanorod sensor was conducted using transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM) to assess the long-term stability of the material. (AU)

• FAPESP's process: 22/14720-4 - From Atoms to Ceramics: A Transmission Electron Microscopy Study on the Development of Transparent Materials
• Grantee: Tarcísio Micheli Perfecto
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 24/15260-2 - Investigation of charge carrier transport in Dion-Jacobson 2D - 3D multidimensional perovskite system for solar conversion.
• Grantee: Gabriela Oliveira Gera
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• FAPESP's process: 24/03388-4 - Influence of electronic and structural defects on In2O3-based sensors decorated with noble metals for detection of microbial volatile organic compounds
• Grantee: Gustavo Sanghikian Marques dos Santos
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 20/06421-1 - Development of sensors derived from metal-organic frameworks to detect microbial volatile organic compounds
• Grantee: Diogo Paschoalini Volanti
• Support Opportunities: Regular Research Grants
• FAPESP's process: 22/05381-1 - ZnO/NiO-type heterostructures derived from metal-organic frameworks for the detection of microbial volatile organic compounds
• Grantee: Reinaldo dos Santos Theodoro
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 24/12700-1 - MnOx/ZnO-based sensors fabricated by the flame spray pyrolysis for microbial volatile organic compounds detection
• Grantee: Reinaldo dos Santos Theodoro
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate