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Meeting Turing Structures in Manmade Interface
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In 1952, Alan Turing, the father of computer science and artificial intelligence, proposed that certain repetitive natural patterns may be produced by the interaction of two specific substances through the "reaction-diffusion" process. In this system, activator promotes the reaction and inhibitor inhibits the reaction. When the two meet, the reaction diffuses. When the difference in diffusion coefficient between the two reaches a certain level, the high diffusion ratio between them will cause the system imbalance and induce the formation of periodic complex patterns.
"Turing structure" exists widely in nature, such as the body patterns of zebras, the phyllotaxis of sunflowers, the follicle spacing of mouse hairs. However, it is difficult to construct a Turing structure in a manmade chemical system since the difference in diffusion coefficients of substances is small.
Recently, Prof. GAO Minrui's group from the University of Science and Technology of China of the Chinese Academy of Sciences created the Turing structure on inorganic transition metal chalcogenides with the "reaction-diffusion" process for the first time. The results were published in German Applied Chemistry and the study was selected as Back Cover.
A cation exchange method was used by the researchers to produce Turing-type Ag2Se on CoSe2 nanobelts based on diffusion-driven instability.
In the binary solution of diethylenetriamine (DETA) and water, the inhibitor, Ag+ reacts with DETA to form Ag(DETA)+. At the same time, the activator, Co2+ overflows from the surface of the cobalt diselenide (CoSe2) nanobelt. When the rapidly diffused Ag(DETA)+ reaches the Nernst layer on the CoSe2 surface, it interacts with the activator Co2+ diffused on the CoSe2 surface, and finally forms a complex and beautiful Ag2Se Turing pattern on the CoSe2 surface.
This resultant Turing-type Ag2Se-CoSe2 material was an efficient oxygen evolution (OER) electrocatalyst. The intrinsic OER activity was linearly related to the length of Ag2Se-CoSe2 interfaces, indicating that this Turing-type interfaces are more active sites for OER.
The study uses the "reaction-diffusion" theory to construct complex Turing structures on inorganic nanostructured materials for the first time, and provides new ideas for the design of cheap catalysts with higher performance.Contact
