Gas sensor response of pure and activated WO3 nanoparticle films made by advanced reactive gas deposition

Au Nanoparticles in Nanocrystalline TiO2−NiO Films for SPR-Based, Selective H2S Gas Sensing

“…74 It has also been reported that exposing metal oxides (like CuO, SnO 2 ,W O 3 ,a n dC r 2 O 3 )t oH 2 S at quite low temperatures (<400°C) usually leads to the formation of metal sulfides, which can then be oxidized by treatment in oxygen or air, resulting in the formation of the initial oxide and of gaseous SO 2 . [75][76][77] The sensing properties of these kinds of materials are related to the different electric conductivity of sulfide species compared to that of the initial oxide: a variation in resistivity is thus generated, which can be easily detected and related to H 2 S content. However, it has been demonstrated by a focused surface science study 78 that H 2 Sa b s o r b e do nT i O 2 reacts at temperatures above 300°C with surface oxygen and forms SO 2 which easily desorbs from TiO 2 .Itisnoteworthythata similar temperature range is required for the gas sensing activity of the presently studied nanocomposites.…”

Nanomateriales para buenos ambientes interiores: electrocromías, sensores y fotocatalizadores

“…Figure 7 shows electron microscopy images of a sample of WO 3 nanoparticles from the work by Reyes et al [57]. More general studies have been reported also by the same authors [60 y 62].…”

“…Gas sensing utilizing layers of WO 3 particles made by AGD has been investigated by Solis et al [52][53][54] and subsequently by Reyes et al [55][56][57][58], and analogous studies of NiO particles were carried out very recently by Luyo et al [59]. Figure 7 shows electron microscopy images of a sample of WO 3 nanoparticles from the work by Reyes et al [57].…”

XPS Characterisation of Vacuum Annealed Nanocrystalline WO3 Films

“…The sensing mechanism is based on changes in bulk resistance of the WO 3 film induced by reactions between the surface and target gases such as CO, H 2 S, NO and NH 3 [2]. As these gases absorb on to the surface they change the electron concentration and also alter the height of the potential barrier between adjacent grains, which an electron must overcome in order for a current to flow.…”