Gas sensing properties of nanostructured bismuth oxychloride

In this work, nanostructured bismuth oxychloride (BiOCl) was prepared by a surfactant-assisted method. Bismuth trichloride and dioctyl sulfosuccinate (AOT) were dissolved in non-aqueous media, producing a fine precipitate. The calcination of the precipitated particles at 180 °C produced 3D hierarchical BiOCl semi-spherical architectures, assembled by microplates. The increase of the calcination temperature to 600 °C produced nanostructured ribbons, which are formed by the stacking of several BiOCl layers. Other microstructures can be formed at different calcination temperatures or by using other surfactants. Thick-films of the as-prepared BiOCl ribbons were made by its direct deposition on alumina substrates. The gas sensing characterization was performed at 300 and 400 °C using alternating current (AC). The tests gases were compressed air, CO, CO2 and O2. Humidity effects were discarded by using the extra dry version of these gases. At 300 °C, reproducible CO gas sensing patterns were obtained; however, the detection of CO2 and O2 produced unreliable results. At 400 °C, reliable gas sensing patterns were obtained in CO, CO2 and O2. According to its gas response, BiOCl behaved as a p-type seminconductor material.