Ionic Liquid Improves Speed and Efficiency of Hydrogen-Producing Catalyst

Ongoing saga of building a better fuel cell catalyst goes holistic

(June 2012)

Results: The design of a nature-inspired material that can make energy-storing hydrogen gas has gone holistic. Usually, tweaking the design of this particular catalyst—a work in progress for cheaper, better fuel cells—results in either faster or more energy-efficient production but not both. Now, researchers at Pacific Northwest National Laboratory have found a condition that creates hydrogen faster without a loss in efficiency.

And, holistically, it requires the entire system—the hydrogen-producing catalyst and the liquid environment in which it works—to overcome the speed-efficiency tradeoff. The results, published online June 8 in the Proceedings of the National Academy of Sciences, provide insights into making better materials for energy production.

Why It Matters: "Our work shows that the liquid medium can improve the catalyst's performance," said chemist Dr. John Roberts of the Center for Molecular Electrocatalysis at Pacific Northwest National Laboratory. "It's an important step in the transformation of laboratory results into useable technology."

Combined with an acidic ionic liquid, this catalyst can make hydrogen gas quickly and efficiently.

The results also provide molecular details into how the catalytic material converts electrical energy into the chemical bonds between hydrogen atoms. This information will help the researchers build better catalysts, ones that are both fast and efficient, and made with the common metal nickel instead of expensive platinum.

For more information, see the PNNL News Center.

Acknowledgments:

Funding: The Center for Molecular Electrocatalysis at PNNL is one of 46 Energy Frontier Research Centers supported by the U.S. Department of Energy Office of Science at national laboratories, universities, and other institutions across the country to accelerate basic research related to energy.

Research Team: Douglas H. Pool, Michael P. Stewart, Molly O'Hagan, Wendy J. Shaw, John A. S. Roberts, R. Morris Bullock, and Daniel L. DuBois, PNNL

Reference: DH Pool, MP Stewart, M O'Hagan, WJ Shaw, JAS Roberts, RM Bullock, and DL DuBois. 2012. "An Acidic Ionic Liquid/Water Solution as Both Medium and Proton Source for Electrocatalytic H₂ Evolution by [Ni(P₂N₂)₂]²⁺ Complexes." Proceedings of the National Academy of Sciences of the United States of America 109(39):15634-15639. DOI:10.1073/pnas.1120208109.