Heteropolyacid-encapsulated TiHY zeolite as an inorganic photosynthetic reaction center mimicking the plant systems

A tremendous breakthrough was required for the researchers trying to find a way to photodecomposition of water by using semiconductor photocatalysts without electricity. In this regard, we attempted to prepare the heteropolyacid (HPA)-encapsulated TiHY zeolite a new photocatalyst mimicking the plant photosynthetic system. This photocatalyst (0.3 g/40 ml) was observed to generate hydrogen (4.08±0.7 μl/h) and oxygen (6.86±0.7 μl/h) from the aqueous solutions upon illumination by two photon reactions (UV and visible lights), which is quite analogous to the “Z-scheme” mechanism for plant photosynthetic systems. The turnover number of the photocatalyst was determined to be 11 with the quantum yield of the water splitting about 27±6% at 352 nm. Thus, this inorganic material must be very useful as a reaction center mimicking the plant photosynthetic system without electrical energy.