Feedback based gas sensing setup for ppb to ppm level sensing

Area of Science:

• Materials Science
• Chemical Engineering
• Sensor Technology

Background:

• Accurate sensing of low-concentration gases, particularly flammable ones like hydrogen, is critical.
• Conventional gas sensing setups struggle with ultra-low concentration detection (parts per billion) without specialized gas cylinders.

Purpose of the Study:

• To develop a versatile, home-built resistance-based gas sensing setup.
• To achieve accurate gas quantification across a wide concentration range (ppb to ppm) and temperature spectrum (77–900 K).

Main Methods:

• Utilized a novel two-chamber dilution system with a feedback assembly for enhanced gas dilution.
• Integrated mass flow controllers for precise gas concentration control.
• Employed palladium and ZnO nanoparticle thin films for calibration and testing.

Main Results:

• The setup accurately senses gas concentrations from parts per billion to parts per million.
• Demonstrated reliable performance across a broad temperature range (77–900 K).
• Achieved good agreement between calculated sensitivity values and published data, validating the design.

Conclusions:

• The developed gas sensing setup offers a cost-effective and accurate solution for detecting ultra-low gas concentrations.
• The innovative dilution method enhances sensitivity without requiring additional mass flow controllers.
• The system's wide operational temperature range and validated performance make it suitable for diverse applications.