Temperature dependence and degradation of gasochromic response behavior in hydrogen sensing with Pt/WO3 thin film

• Published in: Thin solid films Vol. 558; pp. 411 - 415
• Main Authors: Okazaki, S., Johjima, S.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 02.05.2014; Elsevier
• Subjects: Cross-disciplinary physics: materials science; rheology; Degradation; Detection; Deterioration; Exact sciences and technology; Exposure; Gasochromism; Hydrogen; Hydrogen leak detection; Liquid phase epitaxy; deposition from liquid phases (melts, solutions, and surface layers on liquids); Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Physics; Platinum-supported tungsten trioxide; Recovery; Response kinetics; Sensitivity; Thin films; Tungsten oxides; Degradation; Hydrogen leak detection; Gasochromism; Response kinetics; Platinum-supported tungsten trioxide; Temperature dependence; Transmittance; Heat treatments; Thin films; Near infrared radiation; Platinum; Tungsten; Absorption spectra; Sol-gel process
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2014.02.080

The gasochromic characteristics of a sol–gel derived Pt/WO3 film as a hydrogen sensitive material were evaluated at various temperatures using optical transmittance measurements in the near-infrared region. The sensitivity of the film was high and a change of more than 60% in transmittance was observed at room temperature and higher with exposure to a mixture of 4vol%H2 and N2 balance. The response rate was fast and the 90% response time was ca. 10s at 25°C. However, the recovery rate was slower than that of the response, which suggests that the recovery process may not be a reverse reaction of the response mechanism. As the temperature was lowered, the response became slower and weaker, although a reasonable response was still observed at −40°C. However, a deterioration of response behavior at −40°C appeared after the repeated exposure to temperature cycles from −40 to 100°C. Although the sensitivity and response rate became considerably worse after this exposure, the sensing performance was completely restored by heat treatment at 500°C for 1h. •The Pt/WO3 thin film was immobilized on quartz glass substrate by sol–gel method.•The gasochromic responses at temperature range from −40 to +100°C were investigated.•More than 60% transmittance change was observed at room temperature and higher.•The sensitivity and response speed strongly depended on ambient temperature.•The degraded response behavior was restored by the high-temperature heat treatment.