Sol-Gel Pt-VO₂ Films as Selective Chemoresistive and Optical H₂ Gas Sensors

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Sensing

Background:

• Vanadium dioxide (VO₂) is a promising material for gas sensing applications.
• Fabrication methods for VO₂ sensors often involve high energy consumption.
• Enhancing sensor sensitivity and selectivity remains a key challenge.

Purpose of the Study:

• To develop efficient and environmentally friendly VO₂-based hydrogen gas sensors.
• To investigate the effect of nanostructuring and platinum decoration on sensor performance.
• To elucidate the hydrogen sensing mechanism in VO₂.

Main Methods:

• Sol-gel fabrication of VO₂ thin films followed by laser crystallization.
• Decoration of VO₂ surface with platinum nanoparticles (NPs).
• In operando X-ray Diffraction (XRD) and in situ X-ray Photoelectron Spectroscopy (XPS) for mechanism investigation.

Main Results:

• Laser-induced nanostructured Pt/VO₂ sensors exhibited enhanced H₂ response compared to flat films.
• Sensors operated effectively at low temperatures (150 °C) with a detection limit of 2 ppm.
• High selectivity towards H₂, excellent baseline recovery, and long-term stability (>500 h) were achieved.
• The sensing mechanism involves reversible HVO₂ bronze formation and V oxidation state changes.

Conclusions:

• Environmentally friendly laser processing and Pt NP decoration offer a pathway to highly efficient VO₂ H₂ sensors.
• The developed sensors demonstrate potential for practical H₂ detection applications.
• Fundamental understanding of the H₂-VO₂ interaction was advanced through advanced characterization techniques.