Eco-friendly photocatalysts achieved by zeolite fixing

Photocatalysts for pollutant degradation have been extensively investigated but extremely challenging for practical applications, because the radicals formed on the catalyst surface are pernicious to organisms in the nature. We develop a new concept of eco-friendly photocatalyst to impart shape-selective catalysis for pollutants removal but eco-friendly for organisms. The proof-of-concept design is demonstrated by fixing conventional photocatalysts (e.g. TiO 2 , Pt/TiO 2 ) inside of zeolite crystals to form a pomegranate-like structure, as confirmed by electron microscopy and FTIR spectroscopy. In the photodegradation with chlorophyll molecules and grasses as model of the organisms, the zeolite-fixed photocatalysts give ideal performances for the selective degradation of pollutants but are harmless to the organisms, outperforming the conventional photocatalysts. This unique phenomenon is reasonably attributed to the shape-selectivity of the zeolite sheath with uniform micropores, where the pollutant molecules with sizes less than zeolite micropores could be diffused but bulky organisms are hindered to access to the radicals on the TiO 2 surface.