Synthesis, Intercalation And Modification Of Novel Lyered Hdroxides

Intercalation compounds are a family of layered compounds with interlayer species including a variety of molecules and ions. These compounds are widely used in the areas of adsorption, ion exchange, catalyst, ion conductor, etc. so that the host-guest assemble of layered compounds are attracting more and more attention. We describe the synthesis, intercalation and modification of layered hydroxide salt (LHS) and layered double hydroxide (LDH) containing cadmium in this article.(1) We have synthesized layered hydroxide salt Cd₂(OH)3DS·nH₂O (DS=C₁₂H₂₅SO₄^-) with microtube/rod morphology. The microtubes/rods have a diameter of 1-2μm and a length of 5-10μm. The forming of tube/rod is driven by directional growth of rolling layers. The growth process of microtubes/rods under the experimental conditions employed follows a dissolution–recrystallization route.(2) We have synthesized cadmium/gallium containing layered double hydroxide Cd₂Ga(OH)₆NO₃·H₂O with high purity and high crystalinity. Being the same with hydrotalcite, the LDH has the typical rhomblehedral 3R polytype. We have studied the effect of varying reaction conditions and synthesis rute about the formation of the LDH products. Based on the research above, a possible Cd/Ga LDH formation mechanism is speculated. The intercalated NO₃^- can be substituted by a lot of anions such as CrO₄^2-,MnO₄^-,Cl^-,I^-,etc. The anion exchanging property of Cd/Ga LDH is essential for its further use. (3) We have operated the intercalation and modification on the Cd/Ga LDH. According to our experiments, the cadmium-contianing LDH and ioding molecules have some special interactions between each other. We have found that iodine molecules and anions between the LDH layers form a two-dimentional net-like structure which serves as the charge balancing species. Because of the special interaction between Cd/Ga LDH and iodine, the LDH can absorb and release absorbed I2 in both liquid and gaseous phases in modified reaction conditions. Furthermore, we have synthesized CdS nanoparticles based on the Cd/Ga LDH. The nanocomposite shows excellent photovoltage property under visible light. Its potential in photocatalyst and polar cells has yet to be developed.