On the characterization and performance of highly dispersed TiO2 nanoparticles onto BEA zeolite in the continuous gas-phase photooxidation of ethylene†

Two series of TiO₂-based zeolite composites (BEA structures) were prepared by employing a sol–gel method using two different synthesis approaches, i.e., acidic and basic media. Different photocatalytic composites obtained with increasing amounts of TiO₂ (10–50 wt%) were thoroughly characterized and subsequently tested in the photooxidation of ethylene in a continuous gas-phase system. Results showed that sol–gel experimental conditions had a significant effect on the final properties of the samples, as photocatalytic composites obtained under basic conditions showed better TiO₂ dispersion and interaction with the BEA support than their counterparts prepared in an acidic medium. The same photocatalysts showed high performance in ethylene photooxidation, demonstrating complete mineralization and results comparable to or even better than those of the bulk TiO₂ material.