Assembly of Nanoparticles in Zeolite Y for the Photocatalytic Generation of Hydrogen from Water

Synthesis of nanoparticles of TiO2, Pt, CdS, and their binary and ternary combinations were made on zeolite Y starting from molecular precursors that are ion exchanged into the zeolite. Nanoclusters of TiO2 in the anatase form were formed from titanyl ions at low loadings of Ti (1 per 2.5 supercages). CdS (hexagonal form) and metallic Pt were formed from Cd2+ and Pt(NH3)42+ ion exchanged into the zeolite. Binary clusters of TiO2−Pt and TiO2−CdS were also synthesized. Electron microscopy and elemental analysis suggests colocalization of the distinct nanoparticles. Photocatalytic H2 evolution is the strongest indicator of colocalization, since improvements in H2 evolution rates of ∼100 for Pt/TiO2-zeolite over TiO2-zeolite and ∼18 for CDS/TiO2-zeolite Y over CdS-zeolite Y were observed. These improvements exceed colloidal binary systems reported in the literature. However, improvements in the H2 evolution rate of the ternary system Pt/CdS/TiO2 was not as marked, as compared to the best colloidal ternary sys...