Wormlike hematite photoanode breaks the world-record for solar hydrogen production efficiency

September 25, 2013
This is aSchematic Diagram of PEC cell with wormlike hematite photoanode. Credit: UNIST

A research team of Ulsan National Institute of Science and Technology (UNIST), South Korea, developed a "wormlike" hematite photoanode that can convert sunlight and water to clean hydrogen energy with a record-breaking high efficiency of 5.3%.

This research was published in Scientific Reports, a science journal published by the Nature Publishing Group.

The previous record of efficiency among stable oxide semiconductor photoanodes was 4.2% owned by the research group of Prof. Michael Graetzel at the Ecole Polytechnique de Lausanne (EPFL), Switzerland.

Solar is a renewable and sustainable energy production method because it can utilize sunlight, the most abundant energy source on earth, and water, the most abundant natural resource on earth. At the moment, low solar-to-hydrogen conversion efficiency is the most serious hurdle to overcome in the commercialization of this technology.

The key to the solar water splitting technology is the semiconductor photocatalysts that absorb sunlight and split water to hydrogen and oxygen using the absorbed solar energy. Hematite, an iron oxide (the rust of iron, Fe2O3) absorbs an ample amount of sunlight. It has also excellent stability in water, a low price, and environmentally benign characteristics.

Thus it has been a most popular and promising candidate of photoanode material for solar water splitting over the last two decades. However, hematite has a major and critical drawback of an extremely poor electrical conducting property. Thus most of the hematite anodes have exhibited very low performance.

Prof. Jae Sung Lee of UNIST led the joint research with Prof. Kazunari Domen's group at the University of Tokyo, Japan, developing new which has outstanding efficiency.

Prof. Lee and coworkers employed a series of modifications to improve the property of hematite. First, a unique single-crystalline "wormlike" morphology was produced by using a nanomaterial synthesis technique. Second, a small amount of platinum was introduced into the hematite lattice as doping. Finally, a cobalt catalyst was employed to help oxygen evolution reaction. These modifications reduced energy loss due to charge recombination and brought the record-breaking solar-to-hydrogen .

"The efficiency of 10% is needed for practical application of solar water splitting technology. There is still long way to reach that level. Yet, our work has made an important milestone by exceeding 5% level, which has been a psychological barrier in this field," said Prof. Lee. "It has also demonstrated that the carefully designed fabrication and modification strategies are effective to obtain highly efficient photocatalysts and hopefully could lead to our final goal of 10% solar-to-hydrogen efficiency in a near future."

Explore further: Improving performance of a solar fuel catalyst

More information: "Single-crystalline, wormlike hematite photoanodes for efficient solar water splitting", 17 September 2013, Scientific Reports.

Related Stories

Improving performance of a solar fuel catalyst

October 4, 2012

(Phys.org)—Hydrogen gas that is created using solar energy to split water into hydrogen and oxygen has the potential to be a cost-effective fuel source if the efficiency of the catalysts used in the water-splitting process ...

Increasing efficiency of hydrogen production from green algae

April 15, 2013

New research results from Uppsala University, Sweden, instill hope of efficient hydrogen production with green algae being possible in the future, despite the prevailing scepticism based on previous research. The study, which ...

Recommended for you

Antibody-making bacteria promise drug development

August 31, 2015

Monoclonal antibodies, proteins that bind to and destroy foreign invaders in our bodies, routinely are used as therapeutic agents to fight a wide range of maladies including breast cancer, leukemia, asthma, arthritis, psoriasis, ...

Chemists solve major piece of cellular mystery

August 27, 2015

Not just anything is allowed to enter the nucleus, the heart of eukaryotic cells where, among other things, genetic information is stored. A double membrane, called the nuclear envelope, serves as a wall, protecting the contents ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.