Temperature and Pore Size Dependence on the Sensitivity of a Hydrogen Sensor Based on Nanoporous Platinum Thin Films

Nanoporous Pt thin films were prepared by co-sputtering Cu and Pt, followed by dealloying and coarsening. The size of the pores was controlled by the coarsening temperature. The nanoporous Pt thin films had pores ranging from a few nanometers to 35 nm. A resistance transient method was used to measure the sensitivity of these thin films in different hydrogen concentrations using air as the carrier gas. The effect of temperature and pore size on the sensitivity and response time were studied. A sensitivity of 3.5% was obtained for 1000 ppm of hydrogen at room temperature for the largest fabricated pore size of 35 nm. The fabricated sensors showed quick response and repeatability in their sensing mechanism.