Our research interest centers on the development of synthetic methodologies to prepare novel catalytic, electronic, and optical materials. These materials integrate uniform porosity, high surface area, semiconductivity, optical property, photocatalytic, acid- or base-catalytic properties and can have a variety of possible applications.
Synthesis and Characterization of Porous Materials with Controllable Morphology and Composition
Microporous materials are typically crystalline oxides with uniform pore sizes from 3 to 20Å and mesoporous materials cover the pore size range from 20 to 500 Å. Our research in this area is aimed at developing new synthetic methodologies to generate nanoporous materials with unprecedented framework compositions, pore geometry and controllable morphology. The purpose is to find efficient heterogeneous catalysts for industrial chemical reactions or for energy related applications.
Porous chalcogenides possess structural properties characteristic of traditional porous materials such as zeolites, but they generally have better electrical and optical properties. The integration between unform microporosity and electrical/optical properties promises new opportunities in many applications. One interesting property that was recently found is the fast ionic conductivity in a series of hydrated sulfides and selenides. They may also serve as photocatalysts for the production of hydrogen from water (see below).
Synthesis and Organization of Semiconducting Clusters
Quantum confinement in size and dimension can lead to chemical, electrical, and optical properties that are substantially different from those observed for the bulk material. These new properties can lead to numerous technological applications. My research group is interested in exploring new synthetic methodologies to prepare nanoclusters with simultaneous control in size, surface features, and spatial arrangements from zero to three dimensions. We are particularly interested in crystalline nanoclusters with precisely defined compositions and sizes and in their superlattices with various connectivity. One of our recent successes in this area is the synthesis of the largest Cd-S cluster (by single crystal diffraction) containing as many as 54 metal sites.
Porous Semiconductors as Visible-Light Driven Photocatalyst
One important application of porous semiconductors is photocatalysis for the generation of hydrogen fuel from water using visible light. Such photocatalytic process can take advantage of the unique integration of crystalline microporosity and semiconductivity in porous semiconductors. The photocatalytic reduction of water to produce hydrogen fuel has been widely studied during the past several decades, however, nearly all these studies have been confined to condensed semiconductors. So far, efficient catalysts, particular those in visible-light region are rare. We have demonstrated that porous semiconducting chalcogenides can be highly efficient photocatalysts, particularly compared with traditional condensed semiconductors. Impressively, the high activity of these porous photocatalysts does not require the use of any co-catalyst such as Pt.