Study of Physical and Chemical Processes of H₂ Sensing of Pt-Coated WO₃ Nanowire Films

Abstract

H 2 sensors able to operate at room temperature are very important for safe detection of H 2 leakage. We report the large electrical response to H 2 of Pt-coated WO 3 (Pt-WO 3 ) nanowire films without the need of using an external heater. More important, hydrogen sensing processes have been investigated under various conditions, including in air, vacuum filled with pure gas, and a mixture of H 2 and other gases. This is carried out with both electrical and optical methods. The evidence shows that hydrogen will inject into the nanowire and create oxygen vacancy, in addition to reducing adsorbed oxygen at the surface, as is often recognized. It is experimentally demonstrated that the increase of electrical conductivity resulting from the reaction with hydrogen is hampered by coadsorption of O 2 , while N 2 has no such effect. A model has been developed to combine these new findings to give a clearer understanding of the mechanism responsible for H 2 sensing behavior.

Highly selective low-temperature triethylamine sensor based on Ag/Cr2O3 mesoporous microspheres

“…Among these methods, it is thought to be a good approach that metal oxide materials are decorated by noble metals (e.g. Au [12,13,14], Ag [15,16], Pd [17,18], Pt [19,20]) because of their high-activity and non-structure damage to original species. As the cheapest noble metal and the best conductive metal, Ag decoration does not cause a big increase in material budget and can be used as an ideal additive in lowering the working temperature of metal oxide sensing materials.…”

Hetero-nanostructure of silver nanoparticles on MO x (M = Mo, Ti and Si) and their applications

“…It is confirmed that Figure 9 The typical I-V characteristics of the MoO 3 NW@Ag NP thin film sensor toward 500 ppm H 2 at room temperature. H 2 molecules were dissociated into H atom on the metal surface [81,82]. The H atom would interact with the preadsorbed oxygen ions (O 2  ) on the surface of MoO 3 , and then a reaction of H and O 2  was taken placed to form H 2 O molecule [83][84][85].…”

Synthesis and optical properties of Au decorated colloidal tungsten oxide nanoparticles

“…On the other hand, nanostructure materials tend to reveal extremely distinct properties in comparison with bulk type because of higher surface area and lower dimensionality [11,12]. Nowadays, various WO 3 nanostructured including nanowires [13], nanoplates [14], nanorods [15] and nanoparticles [16] have been synthesized by physical or chemical techniques. Pulsed-laser techniques are bringing the rare opportunity to investigate very interesting phenomena which occur in very short time scale [17].…”