Hydrogen sensors based on Pt-loaded WO ₃ sensing layers

Abstract

In this letter we report the enhanced sensing of platinum (Pt)-loaded tungsten oxide (WO 3 ) sensor compared to pure WO 3 sensor towards hydrogen (H 2 ) gas at low operating temperature of 200 °C. The hydrogen sensing of pure and Pt-loaded WO 3 sensors is reported at operating temperatures 200, 300 and 400 °C. The presence of Pt promotes the spillover mechanism and the dissociated H 2 atoms can react with adsorbed/lattice oxygen atoms to release electrons which in turn increases the conductivity of the WO 3 film. The H 2 sensing mechanism of Pt-loaded WO 3 sensor is investigated using micro-Raman spectroscopy. The Raman spectrum of Pt-loaded sensing layer shows a shift of symmetric stretching band from 796 to 804 cm −1 with the introduction of H 2 gas.