XPS studies of active elements surface of gas sensors based on WO3−x nanoparticles

Nanodisperse WO3−x oxides (x ≥ 0) were synthesized by method of electrical explosion of wires. The structure of core levels W4f and O1s was explored by XPS-method. Exposure of oxides to air at 293 K leads to the formation of WO3·(OH2)n-phase on the surface of nanoparticles. A correlation between value x of nonstoichiometric WO3−x oxide matrix and contents of OH-groups in it was revealed. It was noticed, that the increase of number of W5+-states at nanoparticles synthesis leads to rise of the sensor response to molecular hydrogen at room temperature.