SusChEM: Electrocatalysis with Butterfly [2Fe-2S] Clusters The production of hydrogen, the simplest molecule, is a multi-billion dollar industry today that provides hydrogen primarily for combination with nitrogen to produce ammonia fertilizer needed to grow sufficient food for the world population, for removal of sulfur from fossil fuels, and for industrial applications needed to produce the materials for a modern society. Furthermore, one of the grand challenges facing the world today is the need for sustainable, clean, and cost-effective sources of energy and fuels. Hydrogen is a high energy fuel that on burning (or in fuel cells) simply has water as the exhaust product. Unfortunately 96% of the hydrogen produced today is obtained from the expensive action of extremely high temperature and pressure steam on hydrocarbons, a process that is wasteful of both energy and raw materials. Analysis shows that 2% of the world energy is used in these processes and half the world population would not be alive today without the process that uses hydrogen to produce fertilizer for food production. This research project, funded by the Catalysis Program of the Chemistry Division, is exploring the use of electricity to produce hydrogen directly from water in an efficient, clean and sustainable process. To effect the production of hydrogen from water at low temperature and pressure, an inexpensive, readily available catalyst is required. Professors Dennis L. Lichtenberger, Jeffrey Pyun and Richard S. Glass of the University of Arizona and Professor Dennis H. Evans of Purdue University are investigating the production of hydrogen from water using electricity and catalysts composed of inexpensive and plentiful iron and sulfur. The catalysts in this study are inspired by an enzyme found in anaerobic bacteria that produces hydrogen from a [2Fe-2S] cluster site that has a structure denoted as a ?butterfly? type. Although the enzyme generates hydrogen very rapidly, the organometallic butterfly [2Fe-2S] clusters prepared in this project are orders of magnitude faster. The high rates of hydrogen production observed in this project indicate different factors are at play compared to both the biological enzyme and to other inorganic catalysts. This project is exploring the synthesis of new organometallic [2Fe-2S] cluster catalysts and investigating (1) the mechanism that allows for such fast electrocatalytic hydrogen production, (2) the incorporation of the [2Fe-2S] clusters into metallopolymers for increased water solubility and durability of the catalysts, and (3) approaches to achieve high stability of the reactive catalysts in air. The project combines expertise in synthetic organometallic chemistry, polymer chemistry, electrochemistry, and computational chemistry directed toward the fundamental understanding needed to devise efficient electrocatalytic production of molecular hydrogen from water, and educates students in the multidisciplinary and team approaches needed to address complex scientific challenges in the future.