Wendy Shaw: Then and now

WHAT DID THE 2010 EARLY CAREER AWARD ALLOW YOU TO DO?

Dramatic improvements in fuel cell catalyst efficiency are needed to enable widespread use of renewable energy. In my Office of Science Early Career Award, my team and I focused on understanding and mimicking biological features to get synthetic catalysts to work like enzymes--nature's catalysts that are significantly faster and more efficient.

Fuel cells can be used to store energy in chemical bonds, such as by converting hydrogen molecules into protons and electrons. In enzymes, the reaction occurs at the active site, which is surrounded by groups of atoms in a scaffold-like structure. The scaffold is often ignored, but we predicted it was critical to make synthetic catalysts perform as well as enzymes, since it ensures that the hydrogen molecules, protons, and electrons are in the right place at the right time to react quickly.

We added a small scaffold to our synthetic catalysts and found it is indeed critical, and enabled our success. How? First, positioning an extra scaffold group (a carboxylic acid) near the active site of a synthetic catalyst allows protons to move rapidly into and out of the active site, requiring significantly less energy to work. Next, a second set of extra scaffold groups (guanidiniums or aromatics) even further from the active site interact with each other to optimize the active site to split hydrogen molecules, so well that these catalysts now work as efficiently as enzymes.

When directly compared to enzymes in fuel cells, we and our collaborators showed that they had similar performance, a major breakthrough in this field.

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ABOUT:

Wendy Shaw is the director for the Physical Sciences Division at the Department of Energy's Pacific Northwest National Laboratory.

SUPPORTING THE DOE SC MISSION:

The Early Career Award program provides financial support that is foundational to young scientists, freeing them to focus on executing their research goals. The development of outstanding scientists early in their careers is of paramount importance to the Department of Energy Office of Science. By investing in the next generation of researchers, the Office of Science champions lifelong careers in discovery science.

For more information, please go to Early Career Research Program page.

THE 2010 PROJECT ABSTRACT:

Catalyst Biomimics: A Novel Approach in Catalyst Design

The objective of this project is to develop rationally designed proton channels for artificial homogeneous catalysts following principles derived from natural enzyme catalysis. Proton shuttling across or out of organic and/or inorganic molecules is fundamental to a number of energy-relevant reactions, such as hydrocarbon oxidation or hydrogenation and hydrogen production or water splitting. Using energy-minimized computational models of catalysts and reaction pathways, primary and secondary ligands to transition metal catalysts will be rationally designed to promote enhanced reaction rates for that type of reactions; molecular enzyme-mimic catalysts will then be synthesized and characterized; and uses of those novel catalysts in energy conversion and storage reactions will be explored.