Room-temperature gas sensing of laser-modified anatase TiO2 decorated with Au nanoparticles

This article reports on fabrication of activated TiO2 and gold decorated TiO2 prepared by irradiation with millisecond laser and on their gas sensing properties. Commercially available anatase TiO2 was used as starting material whose nanoparticles were modified and decorated upon irradiating its water suspension by pulsed laser. Formation of Au nanoparticles was achieved by laser-induced reduction of Au(III) ions, followed by their deposition onto TiO2 nanoparticle surface. In order to evaluate the effect of gold concentration in Au@TiO2 nanocomposites on their sensing properties, two gold-containing samples with 1 and 5 wt% of Au were prepared. All nanomaterials were characterized by XRD, XPS and SEM methods and then tested as gas sensing devices towards a number of volatile compounds. XPS analysis revealed formation of oxygen vacancies and Ti3+ ions on the TiO2 surface upon laser irradiation, while the latter defects disappeared after decoration with gold. Depending on the degree of Au loading, the samples demonstrated selectivity towards ammonia, acetaldehyde or benzene.