Hydrogen Sensitivity of Pure and MWNTs/WO3 hybrid films

WO3/MWNTs hybrid gas sensitive films were fabricated on alumina substrate by spin-coating method.Structure, morphology and chemical composition of the functionalized MWNTs, as-prepared WO3 nanoparticles and WO3/MWNTs hybrid films were studied by SEM, TEM, XRD and XPS techniques. MWNTs were initially functionalized (f-MWNTs) to enhance dispersion and reaction with WO3 nanoparticles. Our results show that WO3 nanoparticles were nucleated on oxygenated group of f-MWNTs surface in hybrid suspension. After coating and annealing the films at 350 ºC, the conductance measurement of the hybrid WO3/MWNTs films indicates rather linear gas sensitivity as a function of hydrogen concentrations from 0.0024 to 1.14% at 320 oC. Gas sensitivity behaviour has discussed according to increase in surface area as well as development of two types of depletion layers, one at the n-WO3/ p-MWNTs hetero junction and the other at WO3 grain boundaries.

کلیدواژه ها:

Hybrid structure ، Hydrogen sensors ، Tungsten trioxide ، Multiwalled Carbon Nanotubes