Low-temperature ultrasound-promoted synthesis of Cr–TiO2-supported photocatalysts for valorization of glucose and phenol degradation from liquid phase

Novel chromium doped titania zeolite or silica supported photocatalysts were prepared via ultrasonically modified wet impregnation method. In this method, rotary evaporator was coupled with ultrasonic bath. The resulting nanomaterials were characterized by several techniques such as XRD, DR UV–vis, N2 physisorption, XPS, ICP-MS, XRF, HRTEM–EDS and they were subsequently tested for their photocatalytic activities in liquid phase processes: selective oxidation of glucose and total mineralization of phenol. Two carboxylic acids (glucaric acid and gluconic acid) were detected as the liquid phase products in the glucose photo-oxidation and better selectivity was achieved for the photocatalyst supported on zeolite. In phenol photodegradation, although conversion rate was not meaningful (ca. 30% after 4 h illumination time), negligible amounts of harmful phenol-derived compounds were detected in water compared with photodegradation using the commercial P-25 photocatalyst. This ultrasonically improved photocatalysts synthesis method was found to have a significant effect on textural properties, spherical shape, good dispersion and visible-light responsiveness of nanophotocatalysts.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Novel supported Cr–TiO2 photocatalysts synthesized by ultrasound-assisted impregnation technique. ► High glucose selective photo-oxidation to glucaric acid and gluconic acid. ► Photocatalysts with high potential for aqueous phase phenol selective total mineralization and solar chemicals production. ► Production of valuable compounds by a one-pot photocatalytic pathway.