Improving gas sensing performance by oxygen vacancies in sub-stoichiometric WO(3−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.