An enhanced gas sensor based on SiO₂@mesoporous MCM-41 core-shell nanocomposites for SO₂ visual detection

Area of Science:

• Materials Science
• Chemical Sensing
• Nanotechnology

Background:

• Sulfur dioxide (SO2) is a harmful gas requiring effective detection methods.
• Existing SO2 sensors may lack sensitivity, ease of use, or rapid response.
• Core-shell nanostructures offer tunable properties for advanced sensing applications.

Purpose of the Study:

• To develop a novel colorimetric sensor for sulfur dioxide (SO2) detection.
• To investigate the sensing performance of a SiO2@MCM-41 core-shell composite.
• To evaluate the material's potential for naked-eye and in situ SO2 monitoring.

Main Methods:

• Fabrication of a core-shell composite: silicon dioxide core (SiO2) and mesoporous MCM-41 shell.
• Loading the composite with a mixture of zinc chloride (ZnCl2), sodium nitroprusside (SNP), and hexamine as the SO2 indicator.
• Testing sensing properties in solid powder, disc, and gas detection tube (GDT) formats.

Main Results:

• The SiO2@MCM-41 composite exhibited a distinct color change from pale yellow to red upon exposure to SO2.
• The sensor demonstrated a low limit of detection (LOD) of 2 ppm for SO2 in disc form, indicating high sensitivity.
• The gas detection tube configuration showed a linear response to SO2 concentrations between 100-1000 ppm.

Conclusions:

• The developed SiO2@MCM-41 core-shell composite is a promising material for colorimetric SO2 sensing.
• The sensor offers easy, effective, and rapid response capabilities for in situ SO2 detection.
• The naked-eye detection potential and high sensitivity make it suitable for various monitoring applications.