□ A research team led by Professor Su-Il In of the Department of Energy Science & Engineering at DGIST (President Kunwoo Lee), in collaboration with research teams led by Professor Insik In of Korea National University of Transportation, Professor Taegyeong Lee of Hanyang University, and Professor Soorathep Kheawhom of Chulalongkorn University in Thailand, has developed a photocatalytic technology that improves the stability of MXene, an emerging material vulnerable to water, to efficiently convert carbon dioxide into methane. The research team protected the MXene surface with a polymer and combined it with copper (Cu) nanoparticles to enhance catalytic performance, while also elucidating the operating mechanism of the carbon dioxide conversion process.
□ Recently, "carbon capture and utilization" technologies, which go beyond simply capturing and storing carbon dioxide to use it as a feedstock for fuels or chemicals, have been attracting attention. In particular, "artificial photosynthesis," which uses sunlight to convert carbon dioxide into useful fuels such as methane, has drawn considerable interest for its potential to turn greenhouse gases into resources.
□ To improve carbon dioxide conversion efficiency, the research team focused on MXene, a two-dimensional nanomaterial with excellent electrical conductivity. However, MXene has the limitation of being easily oxidized when exposed to water and oxygen, resulting in degraded performance. To address this issue, the team applied a "surface modification" technique that forms a protective layer by bonding an organic polymer to the MXene surface, allowing it to maintain stable performance even in environments where water is present.
□ The team then fabricated a new photocatalyst by combining surface-modified MXene (f-MXene) with reduced TiO₂ (RT), which triggers chemical reactions upon exposure to light, and Cu nanoparticles. The MXene facilitates electron transfer, while the Cu promotes the reaction that converts carbon dioxide into methane, thereby improving the overall reaction efficiency.
□ Experimental results showed that the Cu/f-MXene/RT photocatalyst developed by the research team produced 18.1 μmol/g of methane, demonstrating approximately 200 times higher performance than RT alone. Through experiments and theoretical calculations, the team also confirmed the mechanisms by which surface-modified MXene and Cu nanoparticles facilitate electron transfer and promote methane formation.
□ "This study is significant in that we simultaneously improved the stability of the photocatalyst and its carbon dioxide conversion performance by controlling the surface of MXene, which is vulnerable to water and light," said Professor Su-Il In of DGIST. "We expect this technology to be utilized for carbon resource conversion technology that uses sunlight to convert carbon dioxide into useful fuels such as methane."
□ This research was supported by the Nano & Material Technology Development Program through the National Research Foundation of Korea; the Basic Science Research Program funded by the Ministry of Education; and the Technology Innovation Program funded by the Ministry of Trade, Industry & Energy, among others. The research findings were published in Advanced Energy Materials (IF: 25.5), an international journal in the fields of energy and materials.
