Structural analysis of NiO nanocluster catalysts on SiO₂ by using XAFS measurements

NiO nanocluster catalysts were prepared on a SiO₂ support. Ni K-edge XAFS analysis revealed that the combined structure of NiO and Ni-silicate formed by using [Ni(NH₃)₆]²⁺ as a precursor, whereas pure NiO formed by using Ni-acetylacetonate or Ni- nitrate as a precursor. The obtained NiO nanocluster on Ni-silicate showed the catalytic activity for the oxidative coupling of thiophenol under air atmosphere. The combined structure of NiO and Ni-silicate showed the higher activity than pure NiO nanocluster did. (paper)