Development of Technology to Convert Hard-to-Reduce Greenhouse Gases into Fuel

DGIST Develops High-Efficiency Photocatalyst to Address Climate Change and Energy Depletion

DGIST (President Geonwoo Lee) announced on the 29th that Professor Suil In's team from the Department of Energy Engineering has developed a highly efficient photocatalyst that can convert carbon dioxide (CO2), the main culprit of climate change, into natural gas, simultaneously addressing climate change and energy depletion issues.

The research team led by Professor In Su-il from the Department of Energy Engineering at DGIST is discussing their research content. Photo by DGIST

Abnormal weather occurring worldwide due to global warming threatens human survival. Although it is known that the solution lies in reducing greenhouse gases, implementation is difficult. This is why a scientific approach is crucial.

The scientific community has been researching methods to convert atmospheric carbon dioxide into other forms of substances to reduce greenhouse gases. Photocatalyst technology is used in this process. Photocatalyst technology is an eco-friendly future technology that converts carbon dioxide into useful substances. By utilizing only solar energy and water to transform carbon dioxide into natural gas, it can be usefully applied in daily life as fuel for gas heating and cooling systems and natural gas vehicles.

The research team devised a method to combine ‘cadmium selenide,’ which can effectively absorb visible and infrared light, with ‘titanium dioxide,’ a well-known metal oxide photocatalyst material, to convert carbon dioxide into natural resources while simultaneously increasing efficiency.

Previous studies used photocatalyst materials with crystalline surfaces to increase the efficiency of converting carbon dioxide into high value-added gases. In contrast, this study stands out by achieving higher efficiency in carbon dioxide reduction reactions through photocatalyst materials with amorphous surfaces than when crystalline.

In addition to the enhanced catalytic reaction, the process of converting carbon dioxide into carbon compounds, especially methane fuel, was made easier. Unlike typical photocatalysts that require a high-temperature regeneration process, the amorphous catalyst has the advantage of being regenerable within one minute by supplying oxygen to the reactor without heating.

Electron microscope images of crystalline and amorphous TiO2/CdSe photocatalysts synthesized by the research team. Photo by DGIST

The newly developed ‘amorphous structure titanium dioxide-cadmium selenide photocatalyst (TiO2-CdSe)’ by the research team maintained 99.3% methane conversion performance during the initial 6 hours after 18 hours of photoreaction, which is 4.22 times higher in regeneration capability compared to the ‘crystalline photocatalyst (C-TiO2-CdSe)’ of the same composition.

Professor Suil In of DGIST stated, “This research is significant in that we developed a catalyst with regenerative active sites and elucidated the mechanism of carbon dioxide conversion to methane on the amorphous catalyst through computational chemistry studies,” adding, “We will conduct follow-up research to improve energy loss and long-term stability of the amorphous photocatalyst for future technology commercialization.”

This research was conducted with support from the Ministry of Science and ICT’s ‘Mid-Career Research Program’ and the ‘Korea-China Cooperation Project.’ The research results were published in the prestigious international journal in the energy and environment field, Applied Catalysis B: Environment and Energy (IF: 22.1).

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