Addition of SnO2 over an oxygen deficient zirconium oxide (ZrxOy) and its catalytic evaluation for the photodegradation of phenol in water

Abstract

The ZrSn composites materials were prepared in one pot by chemical co-precipitation method. SnO2 was incorporated to ZrxOy modifying the molar percentage from 1 to 5 mol%. The ZrSn composites were characterized by different techniques: XRD, FTIR, DRS, SEM, N2 physisorption and HR-TEM. The ZrSn composites were dried at 80 °C and thereafter were evaluated in the photodegradation of phenol under UV irradiation. The percentages of degradation and mineralization were determined after a reaction time of 150 min by UV–Vis spectroscopy and Total Organic Carbon analysis (TOC), respectively. The composite containing SnO2 in a 3 mol% showed the highest photoactivity with a 72% of photodegradation, a higher value compared with the obtained with TiO2-P25 (62%). Finally, a possible reaction mechanism was proposed based on certain studies, which allows to follow the formation of the active species •OH, •O2− and h+. The formation of the •OH specie was measured by fluorescence spectroscopy whereas the inhibition of the species •O2− and h+ was determined by UV–Vis spectroscopy. The results showed that the ZrSn composites not promotes the hydroxyl radical formation. In addition, the holes capture showed a full-loss of the photoactivity while the minimization of (•O2−) radicals in the reaction media results in a decrement of the photoactivity. The formation of heterojunctions and the presence of localized states in the synthesized composites offer an excellent alternative for a fast photodegradation of phenol.