Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > Polymer-coated catalyst protects "artificial leaf"

This complex solar cell is coated with two different catalysts and works like an "artificial leaf", using sunlight to split water and yield hydrogen gas.
This complex solar cell is coated with two different catalysts and works like an "artificial leaf", using sunlight to split water and yield hydrogen gas.

Abstract:
Due to the fluctuating availability of solar energy, storage solutions are urgently needed. One option is to use the electrical energy generated inside solar cells to split water by means of electrolysis, in the process yielding hydrogen that can be used for a storable fuel. Researchers at the HZB Institute for Solar Fuels have modified so called superstrate solar cells with their highly efficient architecture in order to obtain hydrogen from water with the help of suitable catalysts. This type of cell works something like an "artificial leaf." But the solar cell rapidly corrodes when placed in the aqueous electrolyte solution. Now, Ph.D. student Diana Stellmach has found a way to prevent corrosion by embedding the catalysts in an electrically conducting polymer and then mounting them onto the solar cell's two contact surfaces, making her the first scientist in all of Europe to have come up with this solution. As a result, the cell's sensitive contacts are sealed to prevent corrosion with a stable yield of approx. 3.7 percent sunlight.

Polymer-coated catalyst protects "artificial leaf"

Berlin, Germany | Posted on June 17th, 2013

Hydrogen stores chemical energy and is highly versatile in terms of its applicability potential. The gas can be converted into fuels like methane as well as methanol or it can generate electricity directly inside fuel cells. Hydrogen can be produced through the electrolytic splitting of water molecules into hydrogen and oxygen by using two electrodes that are coated with suitable catalysts and between which a minimum 1.23 volt tension is generated. The production of hydrogen only becomes interesting if solar energy can be used to produce it. Because that would solve two problems at once: On sunny days, excess electricity could yield hydrogen, which would be available for fuel or to generate electricity at a later point like at night or on days that are overcast.

New approach with complex thin film technologies

At the Helmholtz Centre Berlin for Materials and Energy (HZB) Institute for Solar Fuels, researchers are working on new approaches to realizing this goal. They are using photovoltaic structures made of multiple ultrathin layers of silicon that are custom-made by the Photovoltaic Competence Centre Berlin (PVcomB), another of the HZB's institutes. Since the cell consists of a single - albeit complex - "block," this is known as a monolithic approach. At the Institute for Solar Fuels, the cell's electrical contact surfaces are coated with special catalysts for splitting water. If this cell is placed in dilute sulphuric acid and irradiated with sun-like light, a tension is produced at the contacts that can be used to split water. During this process, it is the catalysts, which speed up the reactions at the contacts, that are critically important.

Protection against corrosion

The PVcomB photovoltaic cells' main advantage is their "superstrate architecture": Light enters through the transparent front contact, which is deposited on the carrier glass; there is no opacity due to catalysts being mounted onto the cells, because they are located on the cell's back side and are in contact with the water/acid mixture. This mixture is aggressive, that is to say, it is corrosive, so much so that Diana Stellmach had to first replace the usual zinc oxide silver back contact with a titanium coat approximately 400 nanometers thick. In a second step, she developed a solution to simultaneously protect the cell against corrosion with the mounting of the catalyst: She mixed nanoparticles of RuO2 with a conducting polymer (PEDOT:PSS) and applied this mixture to the cell's back side contact to act as a catalyst for the production of oxygen. Similarly, platinum nanoparticles, the sites of hydrogen production, were applied to the front contact.

Stable H2-Production

In all, the configuration achieved a degree of efficacy of 3.7 percent and was stable over a minimum 18 hours. "This way, Ms. Stellmach is the first ever scientist anywhere in Europe to have realized this kind of water-splitting solar cell structure," explains Prof. Dr. Sebastian Fiechter. And just maybe anywhere in the World, as photovoltaic membranes with different architectures have proved far less stable.

Yet the fact remains that catalysts like platinum and RuO2 are rather expensive and will ultimately have to give way to less costly types of materials. Diana Stellmach is already working on that as well; she is currently in the process of developing carbon nanorods that are coated with layers of molybdenum sulphide and which serve as catalysts for hydrogen production.

####

For more information, please click here

Contacts:
Sebastian Fiechter

49-308-062-42927

Copyright © Helmholtz Association of German Research Centres

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 Links

Watch the "artificial leaf" in action:

Related News Press

News and information

Nagoya physicists resolve long-standing mystery of structure-less transition: Nagoya University-led team of physicists use a synchrotron radiation X-ray source to probe a so-called 'structure-less' transition and develop a new understanding of molecular conductors August 21st, 2017

Tokai University research: Nanomaterial wrap for improved tissue imaging August 21st, 2017

Silk could improve sensitivity, flexibility of wearable body sensors August 20th, 2017

The power of perovskite: OIST researchers improve perovskite-based technology in the entire energy cycle, from solar cells harnessing power to LED diodes to light the screens of future electronic devices and other lighting applications August 18th, 2017

Videos/Movies

Researchers printed graphene-like materials with inkjet August 17th, 2017

Freeze-dried foam soaks up carbon dioxide: Rice University scientists lead effort to make novel 3-D material August 16th, 2017

Nanotech Advances Future Mobile Devices and Wearable Technology July 5th, 2017

ANU invention may help to protect astronauts from radiation in space July 3rd, 2017

Discoveries

Nagoya physicists resolve long-standing mystery of structure-less transition: Nagoya University-led team of physicists use a synchrotron radiation X-ray source to probe a so-called 'structure-less' transition and develop a new understanding of molecular conductors August 21st, 2017

Tokai University research: Nanomaterial wrap for improved tissue imaging August 21st, 2017

Silk could improve sensitivity, flexibility of wearable body sensors August 20th, 2017

The power of perovskite: OIST researchers improve perovskite-based technology in the entire energy cycle, from solar cells harnessing power to LED diodes to light the screens of future electronic devices and other lighting applications August 18th, 2017

Announcements

Nagoya physicists resolve long-standing mystery of structure-less transition: Nagoya University-led team of physicists use a synchrotron radiation X-ray source to probe a so-called 'structure-less' transition and develop a new understanding of molecular conductors August 21st, 2017

Tokai University research: Nanomaterial wrap for improved tissue imaging August 21st, 2017

Silk could improve sensitivity, flexibility of wearable body sensors August 20th, 2017

The power of perovskite: OIST researchers improve perovskite-based technology in the entire energy cycle, from solar cells harnessing power to LED diodes to light the screens of future electronic devices and other lighting applications August 18th, 2017

Energy

The power of perovskite: OIST researchers improve perovskite-based technology in the entire energy cycle, from solar cells harnessing power to LED diodes to light the screens of future electronic devices and other lighting applications August 18th, 2017

Freeze-dried foam soaks up carbon dioxide: Rice University scientists lead effort to make novel 3-D material August 16th, 2017

Two Scientists Receive Grants to Develop New Materials: Chad Mirkin and Monica Olvera de la Cruz recognized by Sherman Fairchild Foundation August 16th, 2017

Fewer defects from a 2-D approach August 15th, 2017

Solar/Photovoltaic

The power of perovskite: OIST researchers improve perovskite-based technology in the entire energy cycle, from solar cells harnessing power to LED diodes to light the screens of future electronic devices and other lighting applications August 18th, 2017

Fewer defects from a 2-D approach August 15th, 2017

Controlled manipulation: Scientists at FAU are investigating the properties of hybrid systems consisting of carbon nanostructures and a dye August 8th, 2017

Simultaneous Design and Nanomanufacturing Speeds Up Fabrication: Method enhances broadband light absorption in solar cells August 5th, 2017

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