Activated carbon-based coloured titania nanoparticles with high visible radiation absorption and excellent photoactivity in the degradation of emerging drugs of wastewater

Activated carbon/TixOy nanoparticles (CTi) were synthesized by a controlled hydrolysis method under mild conditions of temperature (170–210 °C) and pressure (8 bar). These new materials are presented as visible-light driven photocatalysts with high performance in the degradation of emerging drugs in wastewater, like amoxicillin and paracetamol. The presence of Ti3+ self-structural modified TiO2 was corroborated by XPS and Raman. The TiO2 reduction effectivity and consequently, the photocatalytic activity, is influenced by the treatment temperature and the presence of carbon matrix. The band-gap decreases from 3.1 to 1.7 eV by the addition of carbon during the synthesis of coloured titania at 210 °C and from 3.0 to 1.7 eV by increasing the solvothermal temperature from 170 to 210 °C in the preparation of activated carbon-based coloured titania nanoparticles. The presence of carbon also improves the electron transfer from titania nanoparticles to carbon (confirmed by XPS) minimizing electron-hole recombination. All these factors improve the photocatalytic performance of the synthesized materials under visible irradiation providing a cost-effective method for the degradation of persistent wastewater pollutants. [Display omitted]