MOSCOW, September 25MIET scientists as part of a research team have proposed a new method for obtaining a material that allows the processing of carbon dioxide into methanol under the influence of sunlight. According to them, the developed technology makes it possible to quickly, economically and using simple equipment produce photocatalytic material with improved properties. The research results were published in the scientific journal Nanomaterials.
One of the important directions in the development of green technologies today is the use of inexhaustible natural resources (energy from tides, winds or the sun) not only to generate electricity, but also to carry out chemical processes that require an external source of additional energy.
Chemical processes that occur when a reaction system is irradiated with light are called photocatalytic. Using solar energy, photocatalysts can convert carbon dioxide into fuel (for example, methane or methanol).
Under the influence of radiation, charge carriers – electrons and holes – are generated in the catalyst material. The resulting electron-hole pairs participate in redox reactions, converting carbon dioxide and water into other organic compounds.
Groups of scientists around the world are developing conditions under which the combination of light and catalyst material allows for the highest yield of reaction product at the lowest economic cost. Due to its exceptional mechanical and optical properties, as well as low market cost, titanium dioxide TiO2 is most often used as a basis for photocatalysts.
Often, to improve photocatalytic properties, TiO2-based materials are combined with other semiconductor materials. It is this stage of production that is the most resource-intensive and high-tech, said Andrey Tarasov, a researcher at the Laboratory of Nanomaterials Technology of the National Research University Moscow Institute of Electronic Technology (MIET).
«»When two semiconductors, for example, titanium dioxide and oxide copper are in contact with each other, a heterojunction is formed, which increases the lifetime of charge carriers. As a result, photocatalytic activity increases,” he said.
University scientists, in collaboration with other Russian researchers, proposed a method for forming a composite material from TiO2 and CuO by a very simple and fast method — electrophoretic deposition. This method allows you to control the properties of the deposited material, controlling the composition, morphology and thickness of the formed layer.
«Imagine a magnet that attracts magnetic particles to itself. In the same way, during electrophoretic deposition, charged particles are attracted to an oppositely charged surface. In this case, it is not magnetic lines of force, but electric ones that force the particles to move in a certain direction. The main thing is that the particles have a surface charge. For example, ink (e-ink) in electronic books, with which we are all very familiar, works based on the electrophoretic phenomenon,” said Larisa Sorokina, a researcher at the Laboratory of Nanomaterials Technology at MIET.
The proposed combination of semiconductors made it possible to obtain a material with increased photocatalytic activity compared to the classical photocatalyst based on titanium dioxide. With just 10 mass percent copper oxide in the layer, the efficiency of converting carbon dioxide to methanol doubled, the researchers said.
“Future research will focus on changing the structure of the copper oxide particles, converting them into nanofilaments. Preliminary results demonstrate that the filamentary form of the catalytic nanomaterial may have higher photocatalytic properties compared to powder ones,” added Sorokina.
Research and development of composite photocatalysts is carried out at the Institute of Advanced Materials and Technologies of the National Research University MIET within the framework of grant of the Russian Science Foundation No. 22-19-00654.
MIET is a participant in the state support program for universities of the Russian Federation «Priority-2030».