Improving gas sensing performance by oxygen vacancies in sub-stoichiometric WO3−x

Sub-stoichiometric WO 3− x has provided an alternative platform to investigate oxygen vacancies in gas sensors based on metal-oxides. We present an experimental study on the influence of sub-stoichiometric WO 3− x phase upon gas sensing performance. High-quality WO 3− x nanostructures with several x values (WO 3 , W 19 O 55 , W 5 O 14 , W 18 O 49 ) were synthesized and used to fabricate H 2 S gas sensors. Temperature programmed desorption of oxygen (O 2 -TPD) shows that oxygen absorption behaviors of the as-prepared WO 3− x nanostructures are affected by oxygen vacancies, which played a critical role in the detection of H 2 S at varying temperature range. We find that oxygen vacancies in sub-stoichiometric WO 3− x facilitate the ionosorption process and in turn enhance the performance of the gas sensor. We present an experimental study on the influence of sub-stoichiometric WO 3− x phase upon gas sensing performance. Our work shows that the sub-stoichiometric WO 3− x can be used to enhance the low temperature sensing performance.