Enhanced n-butanol sensing properties of Au modified TiO2 nanorod arrays: A combined experimental and first-principle study

Abstract

In this paper, TiO2 nanorod arrays were grown on FTO via a simple hydrothermal method. Then Au nanoparticles with an average size of ∼ 6 nm were modified on the surface of TiO2 nanorods (NRs) using magnetron sputtering technology. The gas-sensing performance of pristine TiO2 and Au-modified TiO2 samples were systematically tested. The Au/TiO2-based sensors exhibited better gas-sensing properties to n-butanol gas than pristine TiO2 sensors, including high sensitivity, lower working temperature, and faster response and recovery time. And 10 s-Au/TiO2 sensor showed the highest response (S = 25) to 100 ppm n-butanol gas at 240 °C, which was 5 times higher than that of pristine TiO2. Furthermore, the adsorption energies of TiO2 and Au/TiO2 surface to n-butanol molecules were calculated using first-principles calculations. It is revealed that the enhanced n-butanol sensing performance of Au/TiO2 sensor is mainly attributed to the catalytic effects and chemical sensitization of Au toward n-butanol gas. The study confirms that Au-modified TiO2 nanorods have great potential for application in n-butanol sensors.