Enhanced sensing performance of Au-decorated TiO2 nanospheres with hollow structure for formaldehyde detection at room temperature

Abstract

Au-decorated hollow TiO2 nanospheres were synthesized via a template method subsequently followed by the reduction of Au nanoparticles decorated on the surface of TiO2. The diameter of the hollow TiO2 nanospheres is 150–200 nm and the thickness of the shell layer is 10–15 nm. The particle size of Au nanoparticles on the surface of TiO2 nanospheres is about 15 nm. The 1 mol% Au-decorated hollow TiO2 nanospheres based chemiresistive-type sensor exhibited a much improved sensing performance to formaldehyde under Ultraviolet (UV) irradiation at room temperature. The response of the sensor to 5 ppm formaldehyde is about 8.5, which is three times higher than that of the pure hollow TiO2 nanospheres based one. The response and recovery time of the sensor to 5 ppm formaldehyde is 36 s and 110 s, respectively. The mechanisms of both electronic and chemical sensitizations induced by Au nanoparticles and the hollow structure were proposed for the enhanced sensing properties.