Design and Development of Titanium and Vanadium OXide Photocatalysts Incoroprated within Zeolite Cavities and their Photocatalytic Reactivities

Titanium or vanadium oxide species incorporated within the framework of zeolites of mesoporous molecular sieves by an ion-exchange method or Hydrothermal synthesis show high and unique photocatalygic activities for various reactions such as the decomposition of NO into N₂and O₂ or the reduction of CO₂with H₂O to porduce CH₄ and CH₃OH. In situ photo luminescence, XAFS and ESR invertigations revealed tat titanium as well as vanadium oxide moieties exist in highly dispersed tetrahedral coordination states in the zeolite framework and the charge transfer excited state of these transition metal oxide species play a vital role in the photocatalytic reactions on these zeolite and molecular sieve catalysts. The unique physico Chemical properties of porous materials such as pore size, channel structural diminsions, and distribution of ion-exchangeable sites are shown to be important factors in controlling the well as the photocatalygic reactivties and selectivities in various photocatalytic reactions.