Copper ions distribution in synthetic copper-zinc hydrosilicate

Abstract 

Copper ions distribution in the structure of synthetic copper-zinc hydrosilicate of zincsilite structure, obtained non-hydrothermal synthesis have been studied. Zinesilite is referred to the layered silicates of smectite group and is described by the formula Zn_x (Zn_3-x▪_x) [Si₄O₁₀](OH)₂.nH₂O, where Zn_3-x – are the ions located in the octahedral positions of layers, formed by two sheets of [Si₄O₁₀] tetrahedrons; Zn_x are zinc ions in the interlayer; ▪_x are the cation vacancies. Two types of copper ions were distinguished in accordance with the character of their interaction with hydrogen: (1) – substituting zinc ions in the octahedral positions of layers; (2) – substituting zinc ions in the interlayer. These two types of copper ions display the following properties when reacting with hydrogen: (1) – copper ions in octahedral positions start to be reduced at temperatures 553–573 K, and at 723 K reduction degree is 50% ; (2) – copper ions from interlayer start to be reduced at 503–533 K with a constant energy of activation, and their reduction may be complete at this temperature.