Morphology effect dependent on the synthesis method of KxIr1-xO2 system

Keywords:
sol-gel, iridium oxides, solid-state reaction, chemical synthesis

Abstract:
We focus our attention on the synthesis of the solid solution of KxIr1-xO2 with x = 0.25. This solid solution was obtained by the solid-state reaction and sol-gel method using IrO2 and K2CO3 as starting materials. The sample prepared by solid-state reaction was annealed at 630 °C for 186 h and it show a solubility until x = 0.25. We observe the same results at 650 °C. On the other hand, the sol-gel method via acrylamide produces a xerogel that is obtained by dehydration in a microwave. This xerogel was annealing at 630 °C during 186 h. The XRD patterns showed the co-existence of two phases (hollandite, K0.25IrO2 and IrO2) at this temperature. However, further annealing at 650 °C shows a single phase of the solid solution KxIr1-xO2. The morphology of the samples synthesized by solid state reaction and the sol-gel method were observed through Scanning Electron Microscopy (SEM) showing that the method of synthesis of the solid solution of KxIr1-xO2 has as an effect on the morphology. By the sol-gel process we observe very thin fibers of the phase had thickness between 100-150 nm and the solid solution of KxIr1-xO2 obtained by solid-state reaction produce aggregates

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Nanotech 2006 Conference Program Abstract