Heterostructured α-Fe₂ O₃ @ZnO@ZIF-8 Core-Shell Nanowires for a Highly Selective MEMS-Based ppb-Level H₂ S Gas Sensor...

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Sensing

Background:

• Metal oxide semiconductors (MOSs) lack selectivity for H₂S sensing.
• Single MOS@metal organic framework (MOF) core-shell structures exhibit limited sensitivity.
• There is a critical need for highly selective and sensitive H₂S sensors.

Purpose of the Study:

• To develop advanced heterostructured core-shell nanowires for improved H₂S sensing.
• To enhance both selectivity and sensitivity in H₂S gas sensors.
• To create a low-power H₂S gas sensor system for practical applications.

Main Methods:

• Synthesis of heterostructured α-Fe₂O₃@ZnO@ZIF-8 core-shell nanowires (NWs) using atomic layer deposition.
• Characterization of the synthesized NWs for structural and morphological properties.
• Fabrication and testing of a micro-electromechanical system (MEMS) based H₂S gas sensor.

Main Results:

• The α-Fe₂O₃@ZnO@ZIF-8 NWs demonstrated high H₂S response (32.2 to 10 ppm), superior selectivity, and fast response/recovery (18.0/31.8 s).
• Achieved excellent long-term stability (>3 months) and a low limit of detection (200 ppb) at 200 °C.
• Developed a low-power MEMS-based H₂S sensor system with significant application potential.

Conclusions:

• Heterostructured α-Fe₂O₃@ZnO@ZIF-8 core-shell NWs significantly outperform single MOS or MOS@MOF structures for H₂S sensing.
• The designed sensor system exhibits great promise for real-world applications in smart cities and environmental monitoring.
• This work paves the way for next-generation, highly efficient gas sensing technologies.