Humidity-tolerant and highly sensitive gas sensor for hydrogen sulfide based on WO₃ nanocubes modified with CeO₂

Area of Science:

• Materials Science
• Chemical Engineering
• Sensor Technology

Background:

• Ambient humidity significantly hinders the performance of metal oxide semiconductor (MOS) gas sensors.
• Developing humidity-independent gas sensors is crucial for reliable environmental monitoring and industrial safety.

Purpose of the Study:

• To investigate the effect of cerium oxide (CeO2) modification on the gas-sensing properties of tungsten oxide (WO3) nanocubes.
• To evaluate the humidity independence of CeO2/WO3 composite sensors for hydrogen sulfide (H2S) detection.

Main Methods:

• Synthesis of pure WO3 and CeO2-modified WO3 nanocubes using a facile hydrothermal method.
• Characterization of gas-sensing performance in both dry and humid atmospheres at 115 °C.
• Analysis of gas-sensing mechanisms to understand the role of CeO2 modification.

Main Results:

• CeO2/WO3 composite nanocubes exhibited superior gas-sensing properties towards H2S, including high sensitivity and selectivity.
• The humidity independence of CeO2/WO3 sensors was significantly improved compared to pure WO3.
• Response retentions over a wide humidity range were substantially higher for CeO2/WO3 sensors (70.3-76%) than for WO3 sensors (17.9%).

Conclusions:

• CeO2 modification effectively enhances the anti-humidity properties of WO3-based gas sensors.
• The CeO2/WO3 composite presents a promising material for developing robust and reliable H2S gas sensors.
• This study offers a viable strategy for overcoming humidity interference in MOS gas sensing applications.