UNIST research team including Professor Shin Hyung-jun (bottom left) and first author Dr. Son So-dam (bottom right).
[Asia Economy Yeongnam Reporting Headquarters Reporter Hwang Dooyul] A new photocatalyst technology that triggers chemical reactions without light has been developed. This overturns the conventional concept of photocatalysts that require sunlight to react.
The research team led by Professor Shin Hyungjun of the Department of Materials Science and Engineering at Ulsan National Institute of Science and Technology (UNIST) designed a photocatalyst by depositing carbon nanomaterials on top of the existing titanium dioxide photocatalyst, developing a photocatalyst that can remove organic pollutants and sterilize even without sunlight.
The hydroxyl radicals produced by photocatalysts decomposing water break down organic pollutants such as microplastics and waste dyes and have sterilization effects, making photocatalysts applicable in wastewater treatment and air purification technologies.
However, titanium dioxide (TiO2) photocatalysts require activation by high-energy ultraviolet light to decompose water.
The composite catalyst developed by the research team decomposes water and produces hydroxyl radicals without the process of sunlight activating the photocatalyst.
This is explained by the ‘electron acceptor energy level’ formed between titanium dioxide and the carbon nanomaterial fullerene.
In experiments decomposing dye molecules, which represent organic pollutants, in a light-free environment, a 70% dye decomposition effect was observed.
Additionally, when light is present, the existing photocatalyst effect can be utilized, and the photocatalyst can be reused after one use.
Son Sodam, a first author and PhD candidate in the Department of Materials Science and Engineering at UNIST, said, “Since no harmful byproducts are produced after the catalytic reaction, and water can be decomposed by the existing photocatalyst effect during the day, and it is reusable, it can improve the efficiency of water treatment and sterilization technologies.”
The catalyst was designed using an ultra-high resolution scanning tunneling microscope (STM) capable of analyzing the electronic structure within atoms.
The STM analyzed the changes in electronic structure caused by the interaction between titanium dioxide and fullerene molecules, and the catalyst was designed based on this principle.
Electrons (negatively charged particles) in titanium dioxide move to the newly formed ‘electron acceptor energy level,’ leaving only holes (positively charged particles) in titanium dioxide.
When the holes in titanium dioxide meet water molecules, the water molecules decompose, producing hydroxyl radicals.
Corresponding author Professor Shin Hyungjun said, “This research presents atomic-level analysis methods and new material design approaches for photocatalyst development, and it can be widely applied as a platform technology for developing organic-inorganic composite materials made of carbon materials or photocatalysts.”
The research, involving Professor Park Gibok from the Department of Physics and Professor Kim Kwangsoo from the Department of Chemistry at UNIST, was selected as the cover paper of ACS Catalysis, a world-leading journal in the field of catalysis, and was published on the 20th.
The research was supported by the Mid-Career Researcher Support Program and the National Research Foundation under the Ministry of Science and ICT, the Institute for Basic Science, and the National Scientist Support Program.
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