CO sensing properties of macroporous TiO2 thin film enhanced surface activity by using colloidal template

Abstract

Thin films of TiO2 were deposited at room temperature by RF sputtering onto poly (methyl methacrylate) (PMMA) and polystyrene (PS) microsphere templated substrates. The organic template obtained by spin coating method was removed by thermal decomposition at 550 ℃ for 1 hour leaving a TiO2 thin film with size of the original PMMA (300nm) and PS (1µm). This unique morphology enhanced surface activity for applications in gas sensors. The microstructure of TiO2 thin films was investigated by X-ray diffraction, Scanning Electron Microscopy (SEM). The sensitivity of the hemisphere thin films of CO gas was tested as a function of temperature from 300. As a result, this unique morphology enlarged active surface area of TiO2 films and lead to substantially enhanced CO sensitivity and response time. Moreover, in the abstract, the hollow structures (PMMA, PS) have a same surface area that has four times as large as films deposited on untreated substrates, it showed same response regardless of colloidal template size.