Enhanced gas selectivity induced by surface active oxygen in SnO/SnO₂ heterojunction structures at different...

Area of Science:

• Materials Science
• Chemical Engineering
• Nanotechnology

Background:

• Heterojunction structures are crucial for advancing sensing material performance.
• Developing efficient and selective gas sensors is vital for environmental monitoring and safety.

Purpose of the Study:

• To synthesize and characterize 3D hierarchical SnO-SnO2 heterojunction structures for gas sensing applications.
• To investigate the sensing properties, including sensitivity and selectivity, of these heterojunctions towards volatile organic compounds (VOCs).

Main Methods:

• One-pot hydrothermal synthesis was employed to create 3D hierarchical SnO-SnO2 heterojunctions.
• Gas sensing performance was evaluated for ethanol and acetone at different temperatures (180 °C and 280 °C).
• Mechanistic analysis explored the role of surface oxygen species in gas detection.

Main Results:

• The synthesized 3D SnO-SnO2 heterojunctions exhibited high sensitivity towards ethanol (47.69) and acetone (41.56) at 100 ppm.
• Distinctly different sensitivities were observed at 180 °C and 280 °C, indicating temperature selectivity.
• Surface oxygen species (O- and O2-) were identified as key factors influencing temperature-dependent sensing.

Conclusions:

• The 3D hierarchical SnO-SnO2 heterojunctions demonstrate excellent sensitivity, selectivity, and stability for VOC detection.
• The temperature selectivity is attributed to the varying activity of surface oxygen species at different operating temperatures.
• This work provides a new strategy for designing multifunctional sensing materials for practical gas detection applications.