Room-temperature CO Thermoelectric Gas Sensor based on Au/Co₃O₄ Catalyst Tablet

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Monitoring

Background:

• Carbon monoxide (CO) is a toxic gas requiring sensitive detection methods.
• Thermoelectric (TE) gas sensors offer potential for room-temperature operation.
• Developing efficient catalysts is crucial for enhancing TE gas sensor performance.

Purpose of the Study:

• To fabricate and characterize a novel CO thermoelectric gas sensor.
• To investigate the catalytic mechanism and optimize the Au/Co3O4 catalyst.
• To evaluate the sensor's performance at room temperature.

Main Methods:

• Fabrication of Au/Co3O4 catalyst via co-precipitation and tablet compression.
• Characterization using XRD, FESEM, HRTEM, XPS, H2-TPR, FTIR, and BET analysis.
• Assembly of the CO TE gas sensor with the catalyst on a TE film layer.

Main Results:

• Optimal Au/Co3O4 catalyst achieved with 10 wt% Au at 200-300 °C calcination.
• High catalytic activity attributed to small Au nanoparticles, high surface area, Co3+, and water-derived species.
• The sensor exhibited a 23 mV response to 30,000 ppm CO at room temperature, with high selectivity, stability, and a 106 s response time.
• Linear relationship observed between CO concentration (5000-30,000 ppm) and response voltage (ΔV).

Conclusions:

• The developed Au/Co3O4 catalyst significantly enhances CO detection capabilities.
• The room-temperature CO TE gas sensor demonstrates promising performance for practical applications.
• This technology offers a viable alternative for CO gas monitoring.