Highly selective one-dimensional TiO2-based nanostructures for air treatment applications

The aim of the present research is to determine the optimum hydrothermal synthesis procedure for using TiO2-based one-dimensional materials as photocatalysts for air treatment applications, in order to enhance their mineralization capacity. The prepared samples were thoroughly characterized by means of TEM, N2 adsorption–desorption isotherms, XRD and Raman spectroscopy. Trichloroethylene (TCE) was selected as a convenient model volatile organic compound (VOC) due to its elevated reactivity. In this study, it is described how the selection of the synthesis parameters (TiO2 precursor, hydrothermal treatment conditions, washing procedure or calcination temperature) allows modulating the nanotubes physicochemical characteristics and, thus, photoactivity. The optimization process led to nanotubes with remarkable photocatalytic performance, with high TCE conversion and selectivity to CO2, which can be favourably compared to that of the benchmark photocatalyst Degussa P25.

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► Hydrothermal parameters modulate morphology and photoactivity of titanate nanotubes.
► Shoddily defined nanotubes show higher photoactivity due to their larger SBET.
► Increasing calcination temperature boosts the photoactivity of these materials.
► Nanotubes calcined at 300–350 °C exhibit the highest conversion and selectivity.
► Titanate nanotubes present higher selectivity than reference photocatalyst Degussa P25.