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

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, N-2 physisorption and HR-TEM. The ZrSn composites were dried at 80 degrees 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 center dot OH, center dot O2(-) and h(+). The formation of the center dot OH specie was measured by fluorescence spectroscopy whereas the inhibition of the species center dot 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 (center dot 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.

Automated summary

ZrSn composites prepared by chemical co-precipitation method showed good photocatalytic degradation performance towards phenol under UV irradiation, with the composite containing 3 mol% SnO2 exhibiting the highest photoactivity. The proposed reaction mechanism suggests that ZrSn composites do not promote the formation of hydroxyl radicals, and the capture of holes and reduction of (center dot O2(-)) radicals leads to decreased photocatalytic activity. The formation of heterojunctions and presence of localized states in the synthesized composites offer an excellent alternative for fast photodegradation of phenol.