| Budget Amount *help |
¥3,280,000 (Direct Cost: ¥3,100,000、Indirect Cost: ¥180,000)
Fiscal Year 2007: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
Fiscal Year 2006: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2005: ¥1,900,000 (Direct Cost: ¥1,900,000)
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| Research Abstract |
Precious metal-supported mixed metal oxides have received much attention to develop various functional materials including oxidating catalysts. The purpose of the present work is to propose a new technique for the uniform covering of perovskite-type oxides by precious metals. This method is based on the chemical interaction of precious metal ions or these metal complexes with the surface cyano-nitrogens or the surface metal site.
In order to accomplish the present purpose, covering of cyano-bridged heteronuclear coordination polymer, La[Fe (CN)_6]-nH_2O and La[Co (CN)_6]-nH_2O, which have been known to be good precursors of perovskite-type oxides, by Pd (II) and Rh (III) ions was examined.
First, the coordination polymer crystals were immersed in water and an aqueous solution of Pd (NO_3) 2 or Rh (NO_3)_3 was added. After stirring for a while, the crystals were filtered and washed several times with a small amount of water. Results showed that the Pd (II) ions were coordinated by the surface cyano-nitrogens. However, Rh (III) ions did not bind to the cyano-nitrogens. This is probably because the Rh (III) with d^6 electronic configuration is typically inert in the ligand substitution, that is, the substitution of water molecule coordinating to Rh (III) in its aqueous solution by the cyano-nitrogen is extremely slow. So, an aqueous solution of [Rh (C_2O_4)_3]^<3-> was used instead of the aqueous solution of Rh (NO_3)_3-As expected,[Rh (C_2O_4)_3]^<3-> was coordinated to the surface La (III) through the oxalato-bridges.
The present method will be promising for the preparation of precious metal-supported perovskite-type oxides.
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