Hydrogen evolution via water splitting using TiO2 nanoparticles immobilized on aluminosilicate mineral: synergistic effect of porous mineral and TiO2 content

Hydrogen evolution via water splitting was investigated over the nanostructured TiO2/clinoptilolite photocatalyst with the aim of exploring the natural zeolitic support potential and assessing the effect of TiO2 content on the photocomposite reactivity. To this aim, a series of clinoptilolite supported TiO2 photocatalysts varying in titania content (10, 30, and 50 wt.%) were synthesized by facile solid- state dispersion method. The characterization results indicated that clinoptilolite utilization could not only reduce the recombination of electron-hole pairs but also promote the distribution of metallic particles and decrease the TiO2 particle agglomerations. These features were more prominent as 10 wt.% of TiO2 was loaded. Accordingly, supporting TiO2 over natural zeolite helped to boost the hydrogen evolution. The highest photocatalytic activity, 282.48 mu mol/g TiO2 h, was obtained for the TiO2(10%)/natural zeolite sample which was about four times more than that of bare TiO2. However, the excessive loading of TiO2 severely covered the surface of natural zeolite, afforded the aggregations of metallic particles and thereupon, weakened the contact between clinoptilolite and TiO2 and also, the separation efficiency of electron-hole pairs, resulted in the H-2 production loss.