Porous sulfides as visible-light photocatalyst for hydrogen generation from water. DMR-0349326 Pingyun Feng, University

1. Porous sulfides as visible-light photocatalyst for hydrogen generation from water.DMR-0349326Pingyun Feng, University of California-Riverside Developing an efficient process for the production of hydrogen fuel from water using renewable solar energy is one of important steps for meeting the global energy challenge. Towards this goal, a new class of heterogeneous photocatalysts based on crystalline porous sulfide semiconductors has been developed at University of California at Riverside by Prof. Feng and her research group (Angew. Chem. Int. Ed.44, 5299-5303, 2005). Unlike traditional semiconductors that have rather dense structures, these materials contain large cavities within three-dimensional covalent superlattices built from nano-sized supertetrahedral clusters. Such materials integrate porous architecture with tunable electronic bandgap ranging from 2.0 to 3.6eV and can function as visible-light photocatalysts for production of hydrogen from water. A unique feature is that these porous semiconductors are filled with H2O within their channels, which serves to promote H2O reduction through high surface area, large available active sites, and the adjacency of reactant molecules near active sites. In addition, the porous architecture allows easy incorporation of dye sensitizers within their channels that can further enhance photocatalytic response in the visible light region. This work represents the first step toward the development of a new methodology for the development of efficient photocatalysts based on crystalline porous materials.

2. Porous sulfides as visible-light photocatalyst for hydrogen generation from water.DMR-0349326Pingyun Feng, University of California-Riverside The structural and schematic diagrams of representative supertetrahedral clusters, sulfite open-frameworks, and their photocatalytic activity. The photo-excited electrons are used to reduce water to produce hydrogen and holes will be consumed by sacrificial agents: (A) Supertetrahedral cluster denoted as T4. (B) Supertetrahedral cluster denoted as T5. (C) Core-less T4 cluster. Yellow: S2- sites; Red: In3+ sites; Blue: sites for di- or monovalent metals such as Cd, Zn, Mn, Co, Fe, Cu, and Ag. (D) The 3D diamond-type superlattice in a hydrated open-framework copper indium sulfite denoted as ICF-5CuInS-Na. Unconnected spheres are water molecules and Na+ sites.