A Sustainable Solution to Fighting Global Warming – New Catalyst Efficiently Converts CO2 to Natural Gas

Researchers have developed a high-efficiency photocatalyst converting CO2 into methane using cadmium selenide and amorphous titanium dioxide, achieving 99.3% methane conversion with improved regeneration. Future work will focus on enhancing its energy efficiency and stability for commercial use.

A research team at DGIST has developed an advanced photocatalyst that efficiently converts CO2 into methane, potentially offering a sustainable solution to combat global warming.

Professor In Soo-il and his team from the Department of Energy Science & Engineering at DGIST have successfully developed a highly efficient photocatalyst. This innovation is capable of converting carbon dioxide (CO2), a significant factor in climate change, into methane (CH4), commonly known as natural gas.

Global warming causes abnormal climates around the world, threatening the survival of the human race. Reducing greenhouse gases is crucial to solving the increasingly concerning problem of global warming, which requires converting atmospheric carbon dioxide into other substances. Photocatalytic technology is an environmentally friendly solution that converts carbon dioxide into useful substances such as natural gas using only solar energy and water. The natural gas produced can be used in our daily lives as a fuel for heating and cooling systems and vehicles.

Enhancements in Photocatalytic Materials

The research team combined cadmium selenide, which absorbs visible and infrared light, with titanium dioxide—a metal oxide and well-known photocatalytic material—to convert carbon dioxide into natural gas with high efficiency.

Previously, crystalline titanium dioxide, which has a periodic lattice structure, was analyzed as a photocatalytic material. However, the formation of active sites for the trivalent cations of titanium (Ti³⁺) was limited owing to the regular arrangement of the particles. To overcome this problem, Professor In’s team improved the catalytic reaction using amorphous titanium dioxide, which can form more active sites for Ti³⁺ through irregular particle arrangements that lack the periodicity of the lattice structure.

In addition to improved catalysis, the charge-transfer process is stable, ensuring a sufficient supply of electrons to participate in the reaction. This facilitates the conversion of carbon dioxide into carbon compounds, particularly methane fuel. Furthermore, unlike conventional photocatalysts that require high temperatures for regeneration, amorphous catalysts can be regenerated within one minute when oxygen is supplied to the reactor without heating.

High Efficiency and Future Research Directions

The research team’s newly developed amorphous titanium dioxide–cadmium selenide photocatalyst (TiO₂-CdSe) maintained a methane-conversion performance of 99.3% for the first 6 hours after 18 hours of photoreaction, making it 4.22 times more regenerative than the crystalline photocatalyst (C-TiO₂-CdSe) having the same composition.

“This study is significant in that we have developed a catalyst with regenerative active sites and identified the mechanism by which carbon dioxide is converted into methane using an amorphous catalyst through computational chemistry research,” said DGIST Professor In. “We will conduct follow-up research to improve the energy loss of the amorphous photocatalyst and enhance its long-term stability for future commercialization of the technology,” he added.

Reference: “Unravelling the effect of Ti3+/Ti4+ active sites dynamic on reaction pathways in direct gas-solid-phase CO2 photoreduction” by Niket S. Powar, Sanghoon Kim, Junho Lee, Eunhee Gong, Chaitanya B. Hiragond, Dongyun Kim, Tierui Zhang, Minho Kim and Su-Il In, 26 March 2024, Applied Catalysis B: Environment and Energy.
DOI: 10.1016/j.apcatb.2024.124006

This study was supported by the Medium-sized Research Program and the South Korea-China Cooperation Program of the Ministry of Science and ICT.