Career: Catalytic Production of H2 from Water by Molecular Metal Complexes with Pentadentate Ligands

University Of Memphis, Memphis TN

Investigators

Abstract

In this project funded by the Chemical Catalysis program of the Chemistry Division, Professor Xuan Zhao of the University of Memphis is developing new catalysts for the generation of hydrogen (an important chemical feedstock and future fuel) from water and sunlight. To accomplish this, new catalysts that are based on economically attractive metals such as cobalt are being developed. Additionally, the details of how the catalysts function are being determined. This information will provide a guide to form yet more efficient materials to convert water to hydrogen and may be applied to other potential applications such as the reduction of carbon dioxide. The project involves the training of undergraduate and graduate students in catalytic science. An outreach program will provide Memphis area students and faculty at predominantly undergraduate institutions with opportunities to participate in renewable energy research and to learn about solar energy conversion and photocatalysis through weekend workshops, summer research opportunities and local meetings. The central hypothesis of this project is that the complexation of a metal ion by a single polydentate ligand that leaves one open site on the metal will result in stable metal complexes with high catalytic activity toward the photocatalytic reduction of water. The research centers largely on cobalt complexes for which preliminary data supports the hypothesis, but includes other earth abundant metals. In addition to synthetic studies aimed at forming these complexes with a variety of ligands, a detailed mechanistic investigation is being carried out to determine the active species for proton binding and reduction, whether H-H formation occurs through a homolytic or heterolytic pathway, and the general factors that control the mechanism of H2 evolution. The mechanistic studies are being conducted in collaboration with research scientists at Brookhaven National Laboratory.