Characterization of Pt-doped SnO2 catalyst for a high-performance micro gas sensor

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Sensing

Background:

• Tin dioxide (SnO2) is a semiconductor with gas sensing applications.
• Doping SnO2 with platinum (Pt) can enhance its performance.
• Understanding the structural changes in Pt-SnO2 is crucial for optimizing sensor capabilities.

Purpose of the Study:

• To investigate the atomic-scale structure of Pt-SnO2 thin films.
• To determine the effect of platinum concentration on the structure.
• To correlate the local Pt structure with methane sensing activity.

Main Methods:

• Sputter-deposition method for producing Pt-SnO2 thin films.
• Extended X-ray absorption fine structure (EXAFS) analysis.
• X-ray diffraction (XRD) analysis.

Main Results:

• Pt-SnO2 films maintain a rutile structure similar to SnO2 for Pt concentrations <10 at%.
• Platinum ions substitute Sn positions in the rutile structure; no Pt metal clusters form.
• The Pt-SnO2 structure becomes amorphous at Pt concentrations >11 at%.
• A strong correlation exists between methane sensing activity and the local Pt structure.

Conclusions:

• The structural integrity of Pt-SnO2 is dependent on Pt concentration.
• Optimizing Pt concentration is key to achieving high-performance methane sensors.
• The local atomic structure of Pt significantly influences gas sensing properties.