High-Efficiency Solar Hydrogen Production... UNIST and POSTECH Develop Non-Toxic Silicon Photocatalyst

Recently, a photocatalyst capable of producing hydrogen and high value-added compounds based on solar energy has been developed, attracting attention. The developed catalyst is eco-friendly and non-toxic, and is expected to be utilized in the commercialization technology of green hydrogen production.

Professor Jeongki Ryu's team from the Department of Energy and Chemical Engineering at UNIST and Professor Sujin Park's team from the Department of Chemistry at POSTECH jointly conducted research and developed a hybrid silicon photocatalyst capable of simultaneously producing hydrogen and high value-added compounds based on solar energy.

This is a highly stable photocatalyst that compensates for the shortcomings of silicon photocatalysts. Existing catalysts had drawbacks such as being difficult to utilize solar energy or having toxicity that causes carcinogenesis, making them not eco-friendly. In contrast, silicon photocatalysts can absorb visible light, thus having a high utilization rate of solar energy.

They are also attracting attention as non-toxic and eco-friendly photocatalysts because they do not emit harmful chemicals during the production process.

Research on the continuous production of hydrogen and high value-added compounds has rarely been reported due to the lack of suitable catalysts. Even if produced simultaneously, toxic catalysts are used under strong basic conditions, making them difficult to use due to environmental pollution.

Silicon photocatalysts also experience reduced hydrogen production efficiency when reacted for a long time due to the oxide layer formed during the photocatalytic reaction.

Illustration explaining the development of a hybrid photocatalyst for continuous hydrogen and high value-added product generation from solar energy.

The research team uniformly coated nickel-doped graphene quantum dots with a thickness of 2?3 nm on the surface of the silicon photocatalyst to secure high hydrogen production efficiency and stability.

The surface-modified hybrid silicon photocatalyst showed about 28 times higher hydrogen production efficiency (14.2 mmol g-1 h-1) compared to the existing silicon photocatalyst.

In the oxidation reaction, it was confirmed that high value-added compounds could be produced by utilizing biomass, a bio-organism, instead of water. It also secured high stability by maintaining 98% of the original form.

Professor Jeongki Ryu of the Department of Energy and Chemical Engineering explained, “The developed non-toxic and low-cost silicon photocatalyst not only enables high-efficiency hydrogen production due to its high solar absorption rate but also allows the production of aromatic compounds, which is significant as it presents a new solar photocatalyst system.”

Professor Sujin Park of the Department of Chemistry at POSTECH said, “Surface modification with nickel-doped graphene quantum dots is an economical technology that can be applied not only to silicon photocatalysts but also to various photocatalysts, presenting new applications in the energy field.”

This research involved Assistant Professor Yuri Choi from UNIST and integrated MS-PhD course researcher Seongho Choi from POSTECH as first authors. The research results were published in the July 27 issue of Advanced Materials.

The research was conducted with support from the Ministry of Science and ICT and the National Research Foundation of Korea through the ‘Academic Research Support Project - Creative Challenge Research’ and the ‘Fundamental Technology Development Project - Carbon Neutral Technology Development’.

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