KYUDAI NEWS KYUSHU UNIVERSITY CAMPUS MAGAZINE Spring 2013 No.24

14/32

The catalyst was developed by a research collaboration led by Professor Seiji Ogo and the research group comprises CROSS (Comprehensive Research Organization for Science and Society), Ibaraki University and Kyushu University.The catalyst's structure was inspired by natural enzymes called nickel-iron hydrogenases*1. Chemists have been trying to understand how they work for decades. The first breakthrough came in 2007, when Prof. Ogo and coworkers first managed to copy the working of hydrogenases using a nickel-ruthenium molecular catalyst - though ruthenium was more expensive than iron, it pointed the way to a revolution in molecular catalysts for dihydrogen splitting. The substitution of iron for ruthenium not only makes the new catalyst four thousand times cheaper, it also forms a crucial model for explaining how nickel-iron hydrogenases can harness energy from hydrogen so efficiently. The future development of this catalyst will not only make energy generation cheaper, it will also provide chemists with a whole new way to control reactions that use hydrogen molecules as an important building block.BackgroundSupplying safe, clean and sustainable energy is one of the most important challenges of the 21st century. Hydrogen gas is seen as a promising energy carrier for that purpose. Although nickel-iron hydrogenase, is known to extract electrons from hydrogen gas at room temperature and atmospheric pressure, this has never been achieved by synthetic molecules. Prof. Ogo’s research group at Kyushu University previously succeeded in synthesizing a nickel-ruthenium catalyst*2, a synthetic model of nickel-iron hydrogenase , which could extract electrons from hydrogen molecules at room temperature and atmospheric pressure. This catalyst has already been used to develop a molecular fuel cell. However, the use of the expensive precious metal ruthenium was a problem.(Reference prices: nickel: 1.6 yen/g, ruthenium: 240 yen/g, iron: 0.06 yen/g) Technological IssuesThe research group, succeeded in developing a new nickel-iron catalyst*3 by studying nickel-iron hydrogenase, a naturally existing hydrogenase enzyme, as a model, and transferring electrons from hydrogen to electron acceptors (ferrocenium ion, methyl viologen and others) at room temperature and atmospheric pressure*4. Elucidation of the crystal structure indicated that the hydride ion (H–) produced after activation of the hydrogen molecule is combined with iron, rather than nickel, as had been previously thought. Crucially, the artificial catalyst reproduces all the chemical features of the natural nickel-iron hydrogenase.New AchievementsThis research achievement has enabled the elucidation of a hydrogen activation mechanism using nickel-iron hydrogenase, and represents dramatic progress in the study of hydrogen activation using a non-precious metal catalyst. It could lead the way to low-cost hydrogen fuel cell.Professor Seiji OgoI2CNER (International Institute for Carbon-Neutral Energy Research) / Department of Chemistry and Biochemistry, Faculty EngineeringHighlight of Recent ResearchKyudai News No.2413A Cheaper Way to - Inspired by Nature, A new catalyst which can extract electrons from hydrogen gas has been invented. The catalyst is a molecule that relies on cheap iron and nickel and works at room temperature and atmospheric pressure. This development is a crucial step in replacing fossil fuels with renewable energy sources.

※このページを正しく表示するにはFlashPlayer9以上が必要です