Gas sensing properties of nanostructured mixed oxide film prepared by anodizing Zr-W alloy through the alumina nanopores

Nanostructured Zr-W mixed oxide film was prepared via anodizing a sputter-deposited Zr-W alloy layer through nanopores in an anodic alumina layer superimposed on the alloy. The morphology, structure and chemical composition of the film were examined by SEM and XRD. Test sensor employing the ZrO₂-WO₃ mixed oxide film as active layer was fabricated and utilized for detecting H₂ and CO gases of various concentrations (100-1000 ppm) at temperatures up to 300°C. The sensor was fast and highly responsive to hydrogen while showing much weaker and slower response to carbon oxide. The findings are of importance for improving chemical and structural stability of the nanostructured tungsten-oxide-based films and selectivity of gas sensors employing the films.