Free Newsletters - Space News - Defense Alert - Environment Report - Energy Monitor
. 24/7 Space News .




ENERGY TECH
Using rust and water to store solar energy as hydrogen
by Staff Writers
Lausanne, Switzerland (SPX) Nov 13, 2012


File image.

How can solar energy be stored so that it can be available any time, day or night, when the sun shining or not? EPFL scientists are developing a technology that can transform light energy into a clean fuel that has a neutral carbon footprint: hydrogen.

The basic ingredients of the recipe are water and metal oxides, such as iron oxide, better known as rust.

Kevin Sivula and his colleagues purposefully limited themselves to inexpensive materials and easily scalable production processes in order to enable an economically viable method for solar hydrogen production.

The device, still in the experimental stages, is described in an article published in the journal Nature Photonics.

The idea of converting solar energy into hydrogen is not a new one; researchers have been working on it for more than four decades. During the 1990s, EPFL joined the fray, with the research of Michael Gratzel.

With a colleague form University of Geneva, he invented the photoelectrochemical (PEC) tandem solar cell, a technique for producing hydrogen directly from water. Their prototypes shared the same basic principle: a dye-sensitized solar cell - also invented by Michael Gratzel - combined with an oxide-based semiconductor.

The device is completely self-contained. The electrons produced are used to break up water molecules and reform the pieces into oxygen and hydrogen.

In the same liquid, two distinct layers in the device have the job of generating electrons when stimulated by light; an oxide semiconductor, which performs the oxygen evolution reaction, and a dye-sensitized cell, which liberates the hydrogen.

The most expensive part? The glass plate
The team's latest prototype focused on resolving the main outstanding problem with PEC technology: its cost. "A U.S. team managed to attain an impressive efficiency of 12.4%," says Sivula.

"The system is very interesting from a theoretical perspective, but with their method it would cost 10,000 dollars to produce a 10 square centimeter surface."

So the scientists set themselves a limitation from the start - to use only affordable materials and techniques. It wasn't an easy task, but they managed. "The most expensive material in our device is the glass plate," explains Sivula.

The efficiency is still low - between 1.4% and 3.6%, depending on the prototype used. But the technology has great potential.

"With our less expensive concept based on iron oxide, we hope to be able to attain efficiencies of 10% in a few years, for less than $80 per square meter. At that price, we'll be competitive with traditional methods of hydrogen production."

The semiconductor, which performs the oxygen evolution reaction, is just iron oxide. "It's a stable and abundant material. There's no way it will rust any further! But it's one of the worst semiconductors available," Sivula admits.

Silicon-enhanced nano-rust
That's why the iron oxide used by the team is a bit more developed than what you'd find on an old nail. Nanostructured, enhanced with silicon oxide, covered with a nanometer-thin layer of aluminum oxide and cobalt oxide - these treatments optimize the electrochemical properties of the material, but are nonetheless simple to apply.

"We needed to develop easy preparation methods, like ones in which you could just dip or paint the material."

The second part of the device is composed of a dye and titanium dioxide - the basic ingredients of a dye-sensitized solar cell. This second layer lets the electrons transferred by the iron oxide gain enough energy to extract hydrogen from water.

An outstanding potential - up to 16%
The results presented in the Nature Photonics paper represent a breakthrough in performance that has been enabled by recent advances in the study of both the iron oxide and dye-sensitized titanium dioxide, and both of these technologies are rapidly advancing.

Sivula predicts that the tandem cell technology will eventually be able to attain an efficiency of 16% with iron oxide, while still remaining low cost, which is, after all, the attractiveness of the approach.

By making it possible to store solar energy inexpensively, the system developed at EPFL could considerably increase the potential of solar energy to serve as a viable renewable energy source for the future.

.


Related Links
Ecole Polytechnique Federale de Lausanne
Powering The World in the 21st Century at Energy-Daily.com






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News





ENERGY TECH
Symposium Celebrates 25th Anniversary of Superconductivity Breakthrough at UH
Houston TX (SPX) Nov 13, 2012
It was a groundbreaking discovery 25 years ago that remains relevant today - University of Houston physics professor Paul Chu achieved superconductivity at a temperature that would usher in a new era in materials science. To celebrate this historic achievement, the Texas Center for Superconductivity at UH (TcSUH) is hosting a special 25th Anniversary Symposium on Creativity and Innovation on Mon ... read more


ENERGY TECH
China's Chang'e-3 to land on moon next year

Moon crater yields impact clues

Study: Moon basin formed by giant impact

NASA's LADEE Spacecraft Gets Final Science Instrument Installed

ENERGY TECH
Mars orbiter back online after system swap

What Arctic Rocks Say About Mars: An Interview with Hans Amundsen

More Driving And Imaging At 'Matijevic Hill'

Curiosity Team Switches Back to Earth Time

ENERGY TECH
Get some bed rest - all 21 days of it

Latest China military hardware displayed at airshow

Obama Win Keeps NASA's Space Plans on Course

Next steps into the final frontier

ENERGY TECH
Mr Xi in Space

China plans manned space launch in 2013: state media

China to launch manned spacecraft

Tiangong 1 Parked And Waiting As Shenzhou 10 Mission Prep Continues

ENERGY TECH
Crew Prepares for Spacewalk After Progress Docks

Crew Preparing for Cargo Ship, Spacewalk

Russian cargo ship docks with ISS: official

Packed Week Ahead for Six-Member Crew

ENERGY TECH
Arianespace's fourth Spaceport mission with Soyuz ready for fueling

Ariane 5's sixth launch of 2012

Ariane 5 is poised for Arianespace's launch with the EUTELSAT 21B and Star One C3 satellites

Ariane 5 orbits EUTELSAT 21B and Star One C3 satellites

ENERGY TECH
Discovery of a Giant Gap in the Disk of a Sun-like Star May Indicate Multiple Planets

New habitable zone super-Earth found in exosolar system

Cosmic sprinklers explained in active planetary nebula

Nearby six-planet system could be life friendly

ENERGY TECH
Microsoft holds Windows Phone 8 hopes

Making a better invisibility cloak

Head of Windows unit leaves Microsoft

Online TEDTalks hit billion-view milestone




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement