Synthesis, characterization and sensing application of novel semiconductor oxides

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Engineering

Background:

• Tin(IV) oxide (SnO2) is a semiconductor with significant applications in gas sensing.
• Developing SnO2 materials with controlled porosity and high surface area is crucial for improving sensor performance.
• Surfactant-templated synthesis offers a route to mesoporous metal oxides.

Purpose of the Study:

• To synthesize mesoporous SnO2 using a cationic surfactant template.
• To investigate the effect of synthesis parameters, specifically slurry acidity, on SnO2 properties.
• To evaluate the gas sensing performance of the synthesized SnO2, particularly its sensitivity to hydrogen.

Main Methods:

• Mesoporous SnO2 synthesized using N-cetyl-N,N,N-trimethylammonium bromide surfactant.
• Synthesis controlled by adjusting the acidity of the starting slurry (pH 7.15).
• Calcination at 723 K for 10 hours in air to remove surfactant and form the mesoporous structure.
• Characterization using BET surface area analysis, FTIR, thermogravimetry, and differential thermal analysis.
• Gas sensing properties evaluated at 573 K.

Main Results:

• Synthesized SnO2 exhibited a BET surface area of 156.8 m²/g and a pore diameter of 38.4 Å.
• FTIR and thermal analysis confirmed surfactant incorporation within mesopores and complete removal upon calcination (673–723 K).
• Higher surface area SnO2 materials demonstrated significantly improved sensitivity to hydrogen gas at 573 K.

Conclusions:

• Mesoporous SnO2 with high surface area can be effectively synthesized using a surfactant templating method.
• Calcination temperature is critical for complete surfactant removal and achieving desired porosity.
• The gas sensing performance, specifically hydrogen sensitivity, is strongly correlated with the surface area of the SnO2 material.