CO Oxidation Activities of Ni and Pd-TiO2@SiO2 Core-Shell Nanostructures

摘要

We prepared Ni and Pd-modified TiO2@SiO2 core-shell nanostructures and then analyzed them by scanning electron microscopy, optical microscopy, X-ray diffraction crystallography, FT-IR and UV-Visible absorption spectroscopy. In addition, their CO oxidation performance was tested by temperature-programmed mass spectrometry. The CO oxidation activity showed an order of Ni-TiO2@SiO2 (900 °C) < Ni-TiO2@SiO2 (90 °C) < Ni-TiO2@SiO2 (450 °C) in the first CO oxidation run, and greatly improved activity in the same order in the second run. The Tio% (the temperature at 10% CO conversion) corresponds to the CO oxidation rate of 2.8 x 10~(-5) molco gcat~(-1) s~(-1). For Ni-TiO2@SiO2 (450 °C), the T_(10%) was observed at 365 °C in the first run and at 335 °C in the second run. For the Pd-TiO2@SiO2 (450 °C), the Tio% was observed at a much lower temperature of 263 °C in the first CO oxidation run, and at 247 °C in the second run. The CO oxidation activities of transition metal modified TiO2@SiO2 core-shell nanostructures presented herein provide new insights that will be useful in developing catalysts for various environments.