Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Algal protein gives boost to electrochemical water splitting

20.12.2011
Towards artificial photosynthesis for solar hydrogen generation
Water splitting in photo-electrochemical cells to yield hydrogen is a promising way to sustainable fuels. A team of Swiss and US scientists now made major progress in developing highly efficient electrodes – made of an algal protein, thus mimicking a central step in natural photosynthesis.

Photosynthesis is considered the «Holy Grail» in the field of sustainable energy generation because it directly converts solar energy into storable fuel using nothing but water and carbon dioxide (CO2). Scientists have long tried to mimic the underlying natural processes and to optimize them for energy device applications such as photo-electrochemical cells (PEC), which use sunlight to electrochemically split water – and thus directly generate hydrogen, cutting short the more conventional approach using photovoltaic cells for the electrolysis of water.

Traditionally, PEC electrodes are made of semiconducting materials such as metal oxides, some of which are also known for their photocatalytic properties. For quite some time, researchers at Empa’s Laboratory for High Performance Ceramics (LHPC) have been investigating nanoparticles of these materials, for instance titanium dioxide (TiO2), for the neutralization of organic pollutants in air and water. Collaborating with colleagues at the University of Basel and at Argonne National Laboratory in the US, they now succeeded in making a nano-bio PEC electrode, consisting of iron oxide conjugated with a protein from blue-green algae (also known as cyanobacteria), which is twice as efficient in water splitting as iron oxide alone.

Inspired by photosynthesis
Iron oxide, in particular hematite (alpha-Fe2O3), is a promising electrode material for PEC because it is susceptible to visible wavelengths and thus uses sunlight more efficiently than photocatalysts like TiO2, which can only use the UV part of solar radiation. What’s more, hematite is a low-cost and abundant material.

The second ingredient in the novel electrode «recipe» is phycocyanin, a protein from blue-green algae. «I was inspired by the natural photosynthetic machinery of cyanobacteria where phycocyanin acts as a major light-harvesting component. I wanted to make artificial photosynthesis using ceramics and proteins», recalls Debajeet K. Bora who designed the new electrode during his PhD thesis at Empa. «The concept of hematite surface functionalization with proteins was completely novel in PEC research.»

After Bora covalently cross-coupled phycocyanin to hematite nanoparticles that had been immobilized as a thin film, the conjugated hematite absorbed many more photons than without the algal protein. In fact, the induced photocurrent of the hybrid electrode was doubled compared to a «normal» iron oxide electrode.

One tough cookie
Somewhat surprisingly, the light harvesting protein complex does not get destroyed while in contact with a photocatalyst in an alkaline environment under strong illumination. Chemists would have predicted the complete denaturation of biomolecules under such corrosive and aggressive conditions. «Photocatalysts are designed to destroy organic pollutants, which are a burden to the environment. But here we have a different situation», says Artur Braun, group leader at Empa’s LHPC and principal investigator of the study. «There seems to be a delicate balance where organic molecules not only survive harsh photocatalytic conditions, but even convey an additional benefit to ceramic photocatalysts: They double the photocurrent. This is a big step forward».

The project was fully funded by the Swiss Federal Office of Energy (SFOE). Bora who will soon have completed his PhD thesis says he will continue what he started at Empa during a postdoc at the University of California, Berkeley, which he will assume early next year.

Dr. Artur Braun | EurekAlert!
Further information:
http://www.empa.ch

More articles from Power and Electrical Engineering:

nachricht Producing electricity during flight
20.09.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

nachricht Solar-to-fuel system recycles CO2 to make ethanol and ethylene
19.09.2017 | DOE/Lawrence Berkeley National Laboratory

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Rainbow colors reveal cell history: Uncovering β-cell heterogeneity

22.09.2017 | Life Sciences

Penn first in world to treat patient with new radiation technology

22.09.2017 | Medical Engineering

Calculating quietness

22.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>