Ag nanoparticles modified TiO2 spherical heterostructures with enhanced gas-sensing performance

Monodispersed TiO2 spherical colloids with diameters of about 250 nm were prepared by a sol–gel method. Heterostructural Ag–TiO2 spheres were manipulated by surface engineering, in which the Ag nanoparticles with an average size of 10 nm were uniformly distributed on the surface of the TiO2 nanospheres by in situ reduction and growth. The gas-sensing properties of the TiO2 nanospheres and heterostructural Ag–TiO2 nanospheres to ethanol and acetone were measured at 350 °C. The results indicated that Ag nanoparticles greatly enhanced the response, stability and response characteristic of TiO2 nanospheres to the tested gases. Response times of Ag–TiO2 sensor to 30 ppm acetone and 50 ppm ethanol were <5 s.