New material can generate hydrogen from salt and contaminated water

Scientists from Tomsk Polytechnic University together with teams from Prague University of Chemistry and Technology and Jan Evangelista Purkyne University in Ústí nad Labem have developed a new 2-D material to produce hydrogen, which is the basis of alternative energy . The material efficiently generates hydrogen molecules from fresh, salty, and polluted water from exposure to sunlight. The results are published in Applied materials and ACS interfaces.

“Hydrogen is an alternative source of energy. Therefore, the development of hydrogen technologies can become a solution to the global energy challenge. However, there are a number of problems to be solved. In particular, scientists are still looking for methods efficient and environmentally friendly to produce hydrogen. One of the main methods is to decompose water by exposure to sunlight. There is a lot of water on our planet, but only a few methods suitable for salt or contaminated water. Also, few use the spectrum infrared, which is 43% of all sunlight, “says Olga Guselnikova, one of the authors and researcher at the TPU School of Research in Chemistry and Applied Biomedical Sciences.

The developed material is a three layer structure with a thickness of 1 micrometer. The bottom layer is a thin film of gold, the second is made of 10 nanometer platinum, and the third is a film of organic metal structures of chromium compounds and organic molecules.

“During the experiments, we watered the material and sealed the container to take periodic gas samples to determine the amount of hydrogen. Infrared light caused the plasmon resonance to be excited at the surface of the sample. The hot electrons generated in the film gold were transferred to the platinum layer. These electrons initiated the reduction of protons at the interface with the organic layer. If the electrons reach the catalytic centers of the organometallic structures, the latter were also used to reduce protons and obtain hydrogen ” Guselnikova explains.

Experiments have shown that 100 square centimeters of the material can generate 0.5 liters of hydrogen in one hour. It is one of the highest rates recorded for 2-D materials.

“In this case, the organometallic frame also acted as a filter. It filtered impurities and passed already purified water without impurities to the metal layer. It is very important, because, although there is a lot of water on Earth, its main volume is salt water or Therefore, we should be ready to work with this type of water, “he says.

In the future, scientists hope to improve the material to make it efficient for both the infrared and visible spectrum.

“The material already demonstrates some absorption in the visible light spectrum, but its efficiency is slightly lower than in the infrared spectrum. After improvement, it will be possible to say that the material works with 93% of the spectral volume of sunlight ” Guselnikova adds.