Fabrication of aggregated In₂O₃ nanospheres for highly sensitive acetaldehyde gas sensors

The selective detection of dangerous and explosive gases with high sensitivity is serious problem to safety of humans and industrial processes. Small sized nanoparticles aggregated into a nanospheres offer plenty of advantages such as large specific area, greater mass transportation, and diffusion of gas molecules deep inside the material towards efficient gas sensing applications. Herein, In₂O₃ nanoparticles aggregated into nanospheres were synthesized successfully through one step microwave hydrothermal method. The structure, morphology and chemical states of prepared In₂O₃ nanospheres were studied by XRD, TEM and XPS measurements. Furthermore, obtained In₂O₃ nanospheres were applied as a gas sensing layer for acetaldehyde (CH₃CHO) detection. Acetaldehyde is an important volatile organic compound which is highly reactive, toxic and carcinogenic agent. Gas sensor based on In₂O₃ nanospheres shows high sensitivity for a wide range of CH₃CHO concentration (1–100 ppm). Concentration dependent resistances during the exposure and oxidation reaction of CH₃CHO gas were investigated. The obtained results in this work indicate that In₂O₃ nanospheres are prospective candidates for the fabrication of CH₃CHO gas sensors.