Abstract

The herein presented low-power high-frequency (500 kHz) ultrasound-assisted precipitation synthesis (LPHF-US) led to a unique multiphase nano-structured titanium dioxide, grafted with oxygen-containing organic functionalities. The material exhibited a high porosity (surface area 326 m²/​g and total pores volume 0.484 cm³/​g) and heterogeneous surface chemistry. In the used LPHF-US synthetic protocol the energy-demanding calcination step leading to crystallization is eliminated and an organic residue is simultaneously grafted to the surface. That organic residue affects the anatase nanocrystals size (4−7 nm), which are embedded in an amorphous titanium hydroxide network. This nanomaterial showed a superior performance as a heterogenous photocatalyst either in a gaseous phase by decomposing toxic vapors of chemical warfare agents (a mustard-gas surrogate), or in a liquid phase by selectively oxidizing benzyl alcohol, a model lignin-biomass derived compound. The grafted organic phase enhances the catalyst’s photoreactivity under visible light, by acting as a photosensitizer (antenna effect) and/​or as a source of chromophores .