Polyoxometalate Polyhedral Oligomeric Silsesquioxane as Inorganic Organic Hybridmaterials for Photocatalytic Hydrogen Production

Abstract

In this thesis, we reported two different non-covalent and covalent interactions of polyoxometalate (POM) Polyhedral Oligomeric Silsesquioxanes (POSS) hybrid materials for photocatalytic water splitting reaction. In the first work, A new series of visible light responsive and water stable inorganic organic inorganic hybrid materials, such as kegging-POM and POSS with different metals newline{[PW12O40][(NH3CH2CH2CH2)(iBu)7Si8O12]3 (POM(W)-POSS), [PMo12O40][(NH3CH2CH2CH2)(iBu)7Si8O12]3 (POM(Mo)-POSS) and [PMo10V2O40][(NH3CH2CH2CH2)(iBu)7Si8O12]5 (POM(MoV)-POSS)} containing newlinecationic electron donor of amino substituted POSS (aminopropyl heptaisobutyl silsesquioxane) (POSS-NH2)) on anionic electron acceptor of POM have been developed for efficient and sustainable photocatalytic H2 production. It is interesting to note that the synthesized hybrid materials exhibit remarkable photocatalytic H2 production activity under visible light irradiation. The maximum H2 production rate of 485 and#956;molh-1g-1 is achieved using POM with heterometallic sites (MoV)-POSS than the homometallic sites. The remarkable photocatalytic H2 production is mainly attributed to improved charge carrier separation by electron deficient metal sites and a red shift in the absorption as revealed from photoluminescence and UV-vis spectra. Importantly, non-covalent POM- POSS hybrid materials demonstrate excellent water stability during photocatalysis due to the hydrophobicity of the hybrid materials, resulting from the integration of hydrophobic POSS-NH2 with POMs in contrast to free POMs newline