E0004

Zinc Ions And Zinc Sulfide Particles In Gamma-Zirconium Phosphate: Synthesis, X-Ray Characterization. ^aC. Ferragina, ^aR. Di Rocco and ^bL. Petrilli, CNR-^aIMIP, ^bISM, via Salaria Km. 29.300, 00016 Monterotondo (Rome) Italy.

Many methods have been applied to prepare semiconductor clusters and their encapsulation in layered structure as IV group phosphates is of increasing importance as a route to the structural control of chemical reactions. This paper describes the synthesis and X-ray characterization of gamma-zirconium phosphate, (gamma-ZrP), an inorganic ion-exchanger, with zinc sulfide formed particles in situ (gamma-ZrPZnS). The aim of this work was to obtain semiconductors supported. By using the hydrothermal synthesis a fully exchanged material has been obtained (gamma-ZrPZn) with a layered structure. Its interlayer distance d is a little decreased with respect to that of the starting material (11.80Å vs. 12.30Å respectively). The X-rays patterns of the zinc material heated at dehydration different temperatures show that up to 320°C is evident a decrease of d (11.80Å vs. 9.82Å). Up to 750°C, when the dehydration is complete, the material is still layered with d of 9.61Å. At 1100°C a syntherization is evident in the TG-DTA curve and the X-ray patterns are that of zinc-zirconium double phosphate.

A form with half zinc exchanged ions has been also prepared (gamma-ZrPZn_0.5) showing in the X-ray patterns the reflections due both to the gamma-ZrP and to the gamma-ZrPZn. At 1100°C the X-ray diffractogram of this material shows two phases: zirconium zinc double phosphate and zirconium pyrophosphate.

The completely dehydrated gamma-ZrPZn was submitted to the H₂S gas flow for several hours. As a results ZnS particles are formed in the gamma-ZrP host matrix. Both the X-ray patterns and microanalysis measurements show evidence of this. The gamma-ZrPZnS diffractogram is similar to those of its precursor gamma-ZrP, with extra reflections due to the ZnS particles.