Mesostructured pure and copper-catalyzed tungsten oxide for NO2 detection

Abstract Different tungsten oxide mesoporous nanostructures were used as resistive solid state sensor for NO 2 gas detection. The electrical characterization revealed that WO 3 was sensitive to NO 2 , even to low gas concentrations, although differences attributable to its structure were observed. The mesoporous material synthesized as a replica of three-dimensional cubic (KIT-6) silica structure showed better and faster response than two-dimensional hexagonal (SBA-15) structure. The introduction of copper as catalytic additive allowed improving both sensor response and response time. X-ray photoelectron spectroscopy (XPS) measurements showed that copper was mainly placed at the material surface as Cu(I).