Humidity-independent highly selective H₂S sensor based on ruthenium doped In₂O₃ synthesized using bio-template method

Area of Science:

• Materials Science
• Chemical Sensors
• Nanotechnology

Background:

• Developing highly selective and sensitive gas sensors is crucial for environmental monitoring and industrial safety.
• Indium oxide (In2O3) is a promising semiconductor material for gas sensing applications.
• Ruthenium doping can enhance the sensing properties of metal oxides.

Purpose of the Study:

• To fabricate a highly selective hydrogen sulfide (H2S) sensor using ruthenium-doped In2O3.
• To investigate the sensor's performance under different operating conditions, including stationary and pulsed heating.
• To evaluate the sensor's selectivity and response in humid environments.

Main Methods:

• Biotemplate synthesis using purified cellulose impregnated with Indium acetate and Ruthenium acetylacetonate.
• Calcination of the precursor material at 600°C to obtain the nanomaterial.
• Characterization of the nanomaterial's grain size (15-20 nm).
• Testing sensor response and selectivity to H2S and interfering gases (CO, H2, NH3) at various temperatures and heating regimes.

Main Results:

• The sensor exhibited a low limit of detection for H2S, well below 100 ppb.
• A significantly enhanced sensor response was observed under pulsed heating (exceeding 185) compared to stationary heating (52) at 10 ppm H2S and 150°C.
• High selectivity coefficients (∼100, increasing to ∼1000 with temperature modulation) against CO, H2, and NH3 were achieved.
• The sensor maintained its response in a humid atmosphere.

Conclusions:

• Ruthenium doping and biotemplate synthesis are effective strategies for creating high-performance H2S sensors based on In2O3.
• Pulsed heating and temperature modulation significantly improve sensor response and selectivity.
• The developed sensor demonstrates potential for reliable H2S monitoring in various environmental conditions, including humid atmospheres.