Co- and Ni-Doped TiO₂ Nanoparticles Supported on Zeolite Y with Photocatalytic Properties

Zeolite Y samples with microporous and hierarchical structures containing Ti-Ni and Ti-Co oxides were obtained as active photocatalysts. Different Ti amounts (5, 10% TiO2) were supported, followed by the loading of Ni or Co oxides (5%). X-ray diffraction evidenced the presence of TiO2 as an anatase. N-2 adsorption-desorption results showed type IV isotherms for hierarchical zeolite Y samples, and a combination of type IV and I isotherms for zeolite Y samples. UV-Vis diffuse reflectance spectra showed a shift in the absorption band to visible with increasing Ti loading and especially after Co and Ni addition. A significant effect of the support was evidenced for Ti and its interaction with Co/Ni species. The zeolite Y support stabilized Ti in the 4+ oxidation state while hierarchical zeolite Y support favored the formation of Ti3+ species, Ni-0 and Ni2+ and the oxidation of Co to 3+ oxidation state. Photocatalytic activity, under UV and visible light irradiation, was evaluated by the degradation of amoxicillin, used as a model test. The photocatalytic mechanism was investigated using ethanol, p-benzoquinone and KI as & BULL;OH and & BULL;O-2(-) radicals and hole (h(+)) scavengers. The best results were obtained for the immobilized Ni-Ti species on the hierarchical zeolite Y support.