Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > Weizmann Institute Scientists Develop A Unique Approach for Splitting Water into Hydrogen and Oxygen

Abstract:
The design of efficient systems for splitting water into hydrogen and oxygen, driven by sunlight is among the most important challenges facing science today, underpinning the long term potential of hydrogen as a clean, sustainable fuel. But man-made systems that exist today are very inefficient and often require additional use of sacrificial chemical agents. In this context, it is important to establish new mechanisms by which water splitting can take place.

Weizmann Institute Scientists Develop A Unique Approach for Splitting Water into Hydrogen and Oxygen

Israel | Posted on April 6th, 2009

Now, a unique approach developed by Prof. David Milstein and colleagues of the Weizmann Institute's Organic Chemistry Department, provides important steps in overcoming this challenge. During this work, the team demonstrated a new mode of bond generation between oxygen atoms and even defined the mechanism by which it takes place. In fact, it is the generation of oxygen gas by the formation of a bond between two oxygen atoms originating from water molecules that proves to be the bottleneck in the water splitting process. Their results have recently been published in Science.

Nature, by taking a different path, has evolved a very efficient process: photosynthesis - carried out by plants - the source of all oxygen on Earth. Although there has been significant progress towards the understanding of photosynthesis, just how this system functions remains unclear; vast worldwide efforts have been devoted to the development of artificial photosynthetic systems based on metal complexes that serve as catalysts, with little success. (A catalyst is a substance that is able to increase the rate of a chemical reaction without getting used up.)

The new approach that the Weizmann team has recently devised is divided into a sequence of reactions, which leads to the liberation of hydrogen and oxygen in consecutive thermal- and light-driven steps, mediated by a unique ingredient - a special metal complex that Milstein's team designed in previous studies. Moreover, the one that they designed - a metal complex of the element ruthenium - is a "smart" complex in which the metal center and the organic part attached to it cooperate in the cleavage of the water molecule.

The team found that upon mixing this complex with water the bonds between the hydrogen and oxygen atoms break, with one hydrogen atom ending up binding to its organic part, while the remaining hydrogen and oxygen atoms (OH group) bind to its metal center.

This modified version of the complex provides the basis for the next stage of the process: the "heat stage." When the water solution is heated to 100˚C hydrogen gas is released from the complex - a potential source of clean fuel - and another OH group is added to the metal center.
"But the most interesting part is the third ‘light stage,'" says Milstein. "When we exposed this third complex to light at room temperature, not only was oxygen gas produced, but the metal complex also reverted back to its original state, which could be recycled for use in further reactions."

These results are even more remarkable considering that the generation of a bond between two oxygen atoms promoted by a man-made metal complex is a very rare event, and it has been unclear how it can take place. Yet Milstein and his team have also succeeded in identifying an unprecedented mechanism for such a process. Additional experiments have indicated that during the third stage, light provides the energy required to cause the two OH groups to get together to form hydrogen peroxide (H2O2), which quickly breaks up into oxygen and water. "Because hydrogen peroxide is considered a relatively unstable molecule, scientists have always disregarded this step, deeming it implausible; but we have shown otherwise," says Milstein. Moreover, the team has provided evidence showing that the bond between the two oxygen atoms is generated within a single molecule - not between oxygen atoms residing on separate molecules, as commonly believed - and it comes from a single metal center.

Discovery of an efficient artificial catalyst for the sunlight-driven splitting of water into oxygen and hydrogen is a major goal of renewable clean energy research. So far, Milstein's team has demonstrated a mechanism for the formation of hydrogen and oxygen from water, without the need for sacrificial chemical agents, through individual steps, using light. For their next study, they plan to combine these stages to create an efficient catalytic system, bringing those in the field of alternative energy an important step closer to realizing this goal.

Participating in the research were former postdoctoral student Stephan Kohl, Ph.D. student Leonid Schwartsburd and technician Yehoshoa Ben-David all of the Organic Chemistry Department, together with staff scientists Lev Weiner, Leonid Konstantinovski, Linda Shimon and Mark Iron of the Chemical Research Support Department.

####

About Weizmann Institute
The Weizmann Institute of Science in Rehovot, Israel, is one of the world's top-ranking multidisciplinary research institutions. Noted for its wide-ranging exploration of the natural and exact sciences, the Institute is home to 2,600 scientists, students, technicians and supporting staff. Institute research efforts include the search for new ways of fighting disease and hunger, examining leading questions in mathematics and computer science, probing the physics of matter and the universe, creating novel materials and developing new strategies for protecting the environment.

For more information, please click here

Contacts:
Yivsam Azgad
Tel: 972-8-934-3856/2


Copyright © Weizmann Institute

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Nanoparticle reduces targeted cancer drug's toxicity February 11th, 2016

Cima NanoTech Debuts Large Interactive Touch Screens with European Customers at ISE 2016: For the first time in Europe, Cima NanoTech’s wide range of high performance, projected capacitive touch modules are showcased February 11th, 2016

Scientists take nanoparticle snapshots February 10th, 2016

Chemical cages: New technique advances synthetic biology February 10th, 2016

Possible Futures

Chemical cages: New technique advances synthetic biology February 10th, 2016

New thin film transistor may lead to flexible devices: Researchers engineer an electronics first, opening door to flexible electronics February 10th, 2016

Electron's 1-D metallic surface state observed: A step for the prediction of electronic properties of extremely-fine metal nanowires in next-generation semiconductors February 9th, 2016

A fast solidification process makes material crackle February 8th, 2016

Announcements

Nanoparticle reduces targeted cancer drug's toxicity February 11th, 2016

Cima NanoTech Debuts Large Interactive Touch Screens with European Customers at ISE 2016: For the first time in Europe, Cima NanoTech’s wide range of high performance, projected capacitive touch modules are showcased February 11th, 2016

Composite Pipe Long Term Testing Facility February 10th, 2016

Scientists take nanoparticle snapshots February 10th, 2016

Energy

New thin film transistor may lead to flexible devices: Researchers engineer an electronics first, opening door to flexible electronics February 10th, 2016

Canadian physicists discover new properties of superconductivity February 8th, 2016

Host-guest nanowires for efficient water splitting and solar energy storage February 7th, 2016

February 4th, 2016

Water

Highly efficient heavy metal ions filter January 25th, 2016

Louisiana Tech University student coauthors research in ACS journal January 15th, 2016

Coated Magnetic Nanoparticles Used to Purify Contaminated Water December 28th, 2015

Photocatalytic Nanostructures Show Ability to Purify Wastewater December 24th, 2015

NanoNews-Digest
The latest news from around the world, FREE




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







Car Brands
Buy website traffic