(478g) A Novel Nanostructured Photocatalyst for Solar Hydrogen Production from Hydrogen Sulfide

The decomposion of hydrogen sulfide has attained a lot of significance due to environmental problem. The Claus process is the most popular process that currently used for the hydrogen sulfide decomposition. The conventional Claus process is involved the synproportionation reaction between H2S and SO2 yielding elemental sulfur and water vapor. Two hydrogens in H2S are wasted to make H2O. If we could recover hydrogen from H2S, instead of oxidizing it into H2O (Claus process), immense amount of hydrogen could be produced. Photocleavage of the H2S to H2 by semiconductor particle photocatalyst has been considered as a process that ultimately converts solar energy into fuels. This process requires less energy compared to photodecomposition of water.

In this connection, we sought a nanostructured photocatalyst with high activity for solar-hydrogen production. The spinel semiconductors with different nanostructures and morphology have immense importance for photocatalyst and other potential applications. We report here, a chemically stable cubic spinel nanostructured CdIn2S4, as a visible-light driven photocatalyst prepared by a facile hydrothermal method. Pretty marigold flower-like morphology was observed in aqueous mediated CdIn2S4 where as, well crystallined nanotubes of 25nm in diameter were obtained in methanol mediated CdIn2S4. The aqueous and methanol mediated CdIn2S4 showed an excellent photocatalytic activity as compared to other organic mediated samples attributed to high degree of crystallinity. The CdIn2S4 photocatalyst gave 16.8% (marigold flower-like morphology) and 17.1% (nanotube) of quantum yields at 500 nm, respectively for the H2 evolution reaction. The details of the characteristics of photocatalyst such as crystal and band structure have been reported. Considering the importance of hydrogen energy, CdIn2S4 will be an excellent candidate as a catalyst for photohydrogen production under visible light. Being a nanostructured chalcogenides semiconductor (with nanotubes), CdIn2S4 will have other potential prospective applications such as in solar cells, LED and optoelectronic devices.

Key word : Nanostructure, CdIn2S4, Photocatalyst, Solar Energy, Hydrogen