Solar Hydrogen Production Made More Efficient Using “Wormlike” Hematite Photoanode

Schematic Diagram of PEC cell with wormlike hematite photoanode. (Credit: Copyright UNIST)
Schematic Diagram of PEC cell with wormlike hematite photoanode. (Credit: Copyright UNIST)

Researchers from the Ulsan National Institute of Science and Technology (UNIST), South Korea, have discovered a more efficient way to convert sunlight and water to clean hydrogen energy. The previous efficiency record of 4.2% was beaten and moved up to 5.3% due to the development of a “wormlike” Hematite Photoanode.

Solar water splitting is a very sustainable energy production method because both water and sunlight are renewable sources. The only obstacle has been finding an efficient way to do this. A regular Hematite overcomes this obstacle due to its ability to absorb a large amount of sunlight, stability in water, availability and low price, and has little environmental impact. The hematite exhibits one flaw however, its poor electrical conductivity.

This issue of conductivity has put serious limitations on the efficiency of solar hydrogen production. However, modifications to the hematite have overcome this. A “wormlike” morphology was produced, a small amount of platinum was introduced into the hematite lattice as doping, and finally a cobalt catalyst was utilized to aid oxygen evolution reaction. These improvements helped reduce energy loss and increased efficiency.

Though this is a great achievement, “The efficiency of 10% is needed for practical application of solar water splitting technology…Yet, our work has made an important milestone by exceeding the 5% level, which has been a psychological barrier in this field,” said lead researcher Jae Sung Lee of UNIST. This achievement has demonstrated that we are on our way to achieve 100% sustainability for solar hydrogen production.


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