Hydrogen sensors based on Pt-loaded WO₃ sensing layers

¹ Department of Optoelectronics, University of Kerala - Kariavattom, Thiruvananthapuram, Kerala 695581, India
² Department of Physics, Govt. College Kariavattom - Thiruvananthapuram, Kerala 695581, India
³ Institute for Sensor and Information Systems (ISIS), Karlsruhe University of Applied Sciences - Moltkestr. 30, D-76133, Karlsruhe, Germany
⁴ Natural Science and Science Education, National Institute of Education, Nanyang Technological University Singapore 637616
⁵ Division of Manufacturing Engineering, School of Mechanical and Aerospace Engineering, Nanyang Technological University - Singapore 637616.

Received: 11 May 2016
Accepted: 4 July 2016

Abstract

In this letter we report the enhanced sensing of platinum (Pt)-loaded tungsten oxide (WO₃) sensor compared to pure WO₃ sensor towards hydrogen (H₂) gas at low operating temperature of 200 °C. The hydrogen sensing of pure and Pt-loaded WO₃ sensors is reported at operating temperatures 200, 300 and 400 °C. The presence of Pt promotes the spillover mechanism and the dissociated H₂ atoms can react with adsorbed/lattice oxygen atoms to release electrons which in turn increases the conductivity of the WO₃ film. The H₂ sensing mechanism of Pt-loaded WO₃ 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 H₂ gas.