Issue 21, 2005

Hydrogen cycling by enzymes: electrocatalysis and implications for future energy technology

Abstract

Hydrogenases provide an inspiration for future energy technologies. The active sites of these microbial enzymes contain Fe or Ni and Fe coordinated by CO and CN ligands: yet they have activities for hydrogen cycling that compare with Pt catalysts. Is there a future for enzymes in technological H2 cycling? There are obviously going to be disadvantages, perhaps overwhelming, as enzymes are notoriously fragile; yet what are the positive aspects and can we learn any chemistry that might be applied to produce the electrolytic and fuel cell catalysts of the future? We have developed a suite of novel electrochemical experiments to probe the chemistry of hydrogenases. The reactions are controlled and monitored at the surface of a small electrode, and characteristic catalytic properties are discernible from tiny amounts of sample material, so this approach can be used to search the microbial world for the best catalysts. Although electrochemistry does not provide structural information directly, it does give a “road map” by which to navigate the pathways and conditions that lead to particular states of the enzymes. This has prompted many interdisciplinary collaborations with other scientists who have provided microbiological, spectroscopic and structural contexts for this work. This article describes how these electrochemical experiments are set up, the data are analysed, and the results interpreted. We have determined mechanisms of catalysis, electron transfer, activation and inactivation, and defined important properties such as O2 tolerance and CO resistance in physical terms. Using an O2-tolerant hydrogenase, we have demonstrated a “proof of concept” miniature fuel cell that will run on a mixed H2/O2 feed in aqueous solution.

Graphical abstract: Hydrogen cycling by enzymes: electrocatalysis and implications for future energy technology

Article information

Article type
Perspective
Submitted
15 Jun 2005
Accepted
04 Jul 2005
First published
21 Sep 2005

Dalton Trans., 2005, 3397-3403

Hydrogen cycling by enzymes: electrocatalysis and implications for future energy technology

K. A. Vincent, J. A. Cracknell, A. Parkin and F. A. Armstrong, Dalton Trans., 2005, 3397 DOI: 10.1039/B508520A

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements