The photo is sourced from rscf.ru
The crystals formed by atoms of transition metals, sulfur and selenium, have the formula XMY (where M is a metal, and X and Y are metalloids). These are structures consisting of several weakly bound layers. The monolayers (densely packed layers of atoms) resemble some kind of “molecular sandwich” with three rows of atoms. The top and bottom layers consist of chalcogens, elements belonging with the sixteenth group of the periodic table (which include sulfur and selenium). Between these layers, there is a central strip of metals such as vanadium, molybdenum or tungsten. The monolayers whose upper and lower rows of chalcogen atoms consist of different elements are called Janus structures. These can be used to accelerate the artificial photosynthesis reaction, where water molecule is split into hydrogen and oxygen under the influence of light.
Scientists from N.M.Emanuel Institute for Biochemical Physics (Russian Academy of Sciences), V.S.Sobolev Institute for Geology and Mineralogy (Siberian Branch of the Russian Academy of Sciences), Novosibirsk State University and Samara State Technical University have performed a search for Janus structures using quantum chemical methods and structure prediction algorithms. Eight new monolayers were discovered with various nature and composition of atomic bonds, which affected the potential stability of compounds. For instance, the layer formed by chalcogens and vanadium turned out to be stronger than the layer formed by chalcogens and molybdenum.
“We have managed to discover new stable Janus structures; most of them are unique and have no analogues in the existing databases. Our study of the structure and properties of these Janus structures will promote their future practical use. At the moment, we are evaluating the prospect of their application in water decomposition reaction”, the Russian Science Foundation quotes Pavel Gavryushkin, Candidate of Technical Sciences from N.M.Emanuel Institute for Biochemical Physics (Russian Academy of Sciences).
In his interview with the Vesti v Elektroenergetike (“News of the Electric Power Industry”) magazine, Suleyman Allakhverdiev, laureate of the Global Energy Prize, said that the artificial photosynthesis was still undergoing the stage of experimental research. “The introduction of such technologies into Russia’s, or even global, fuel and energy complex seems unlikely as of today. Quite intensive laboratory research is still needed, as well as the creation and multifaceted testing of numerous experimental prototypes of artificial photosynthesis devices”, he emphasised.
