Preparation of Co₃O₄/In₂O₃ Nanobundles and Their High Formaldehyde-Sensitive Properties

Abstract:

Formaldehyde is an indoor pollutant that poses a risk to human health, and prolonged exposure may lead to various diseases. Therefore, highly sensitive and selective detection technologies are needed to accurately monitor formaldehyde concentrations. In₂O₃ is a commonly-used semiconductor material in gas sensing. However, the gas sensing performance of pure In₂O₃ sensors falls far from expectation and the construction of heterojunctions is an effective strategy to resolve such issue. In this study, indium oxide-based composites (Co₃O₄/In₂O₃) with a typical p-n heterojunction were synthesized via a simple template-free hydrothermal method for high-performance formaldehyde sensing. XRD, SEM, TEM, and XPS confirmed the p-n heterojunction formation and its positive impact on enhancing surface reactivity. Gas-sensing tests demonstrated that the 3 wt% Co₃O₄/In₂O₃ sensor exhibited optimal performance. The 3 wt% Co₃O₄/In₂O₃ sensor exhibited a response value of 11.1 to 100 ppm formaldehyde at 300°C that was threefold higher than that of pure In₂O₃ (3.77); its recovery time was 41 seconds quicker than that of In₂O₃ (73 s vs. 114 s). The sensor also showed excellent selectivity, reproducibility, and stability. This research presents a scalable, heterojunction-driven design concept for the next generation of gas sensors.

• Periodical: Journal of Nano Research (Volume 91)
• Pages: 51-65
• DOI: https://doi.org/10.4028/p-78dG59
• Online since: March 2026
• Authors: Xiao Dong Wang*, Wen Ge Wang, Juan Mei Zhou, Ya Ping Zhang
• Keywords: Co₃O₄/In₂O₃, Gas Sensor, Hydrothermal Method, In₂O₃ , p-n Heterojunction

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