A DGIST research team has developed an advanced photocatalyst that efficiently converts CO2 into methane, offering a potentially sustainable solution to combat global warming. Professor In Soo Il and his team from the DGIST Department of Energy and Engineering have successfully developed a highly efficient photocatalyst. This innovation has the capacity to convert carbon dioxide (CO2), a major contributor to climate change, into methane (CH4), commonly known as natural gas.
Global warming is causing abnormal climates around the world and threatening the survival of the human race. Reducing greenhouse gas emissions is critical to addressing the growing concern about 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. Extracted natural gas can be used as fuel in heating, cooling systems and vehicles in our daily lives.
Improvement of photocatalytic materials
The research team combined cadmium selenide, which absorbs visible and infrared light, with titanium dioxide, a metal oxide and a 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 centers for trivalent titanium cations (Ti)3+) was limited due to the regular arrangement of particles. To overcome this problem, Professor Ying’s team improved the catalytic reaction using amorphous titanium dioxide, which can create more active sites for Ti.3+ Due to the irregular arrangement of particles that do not have the periodicity of the lattice structure.
In addition to improved catalysis, the charge transfer process is stable and provides sufficient electrons to participate in the reaction. This contributes to the conversion of carbon dioxide into carbon compounds, especially methane fuel. Furthermore, unlike traditional photocatalysts that require high temperatures for regeneration, amorphous catalysts can be regenerated within a minute when oxygen is fed into the reactor without heating.
High efficiency and future research directions
An amorphous photocatalyst composed of titanium dioxide and cadmium selenide (TiO)2-CdSe) maintained a methane conversion efficiency of 99.3% for the first 6 h after 18 h of photoreaction, making it 4.22 times more regenerative than the crystalline photocatalyst (C-TiO).2-CdSe) has the same composition.
“This research is important because we developed a catalyst with regenerative active sites and identified the mechanism by which carbon dioxide is converted to methane using an amorphous catalyst through computational chemistry,” said DGIST Professor Ying. “We will conduct further research to reduce the energy loss of the amorphous photocatalyst and improve its long-term stability for future commercialization of the technology,” he added.