Graphene oxide/polyaniline-based microwave split-ring resonator: A versatile platform towards ammonia sensing.

Area of Science:

• Materials Science
• Chemical Sensing
• Nanotechnology

Background:

• Ammonia gas sensing is crucial for emission control, food safety, and disease diagnosis via breath analysis.
• Existing sensors often require improvement in sensitivity, selectivity, and stability for practical applications.

Purpose of the Study:

• To develop a highly sensitive microwave-based split-ring resonator (SRR) sensor for detecting ammonia gas at low concentrations.
• To investigate the performance of a polyaniline (PANI) and graphene oxide (GO) nanocomposite for ammonia gas sensing.

Main Methods:

• Fabrication of a PANI/GO nanocomposite by in-situ polymerization of aniline over GO sheets.
• Utilizing a microwave-based split-ring resonator (SRR) platform to detect ammonia gas.
• Characterization of sensor sensitivity, selectivity, response time, and repeatability.

Main Results:

• The PANI/GO nanocomposite sensor exhibited high sensitivity to ammonia gas (0.038 dB ppm⁻¹ for 1-25 ppm and 0.0045 dB ppm⁻¹ for >25 ppm).
• The sensor demonstrated selective detection of ammonia in the presence of other gases and across a wide humidity range (15-90%).
• The sensor showed excellent repeatability over 30 days with <0.32% deviation and a response time of 150-400 s at room temperature.

Conclusions:

• The developed PANI/GO nanocomposite SRR sensor offers enhanced sensitivity and selectivity for ammonia gas detection.
• This low-cost, robust sensor is suitable for real-time monitoring in medical, environmental, food, and agricultural applications.
• The sensor's stability and performance highlight its potential for practical ammonia gas sensing solutions.