Au/CuO x -TiO 2 Catalysts for CO Oxidation at Low Temperature

Abstract

A series of Au/CuO x-TiO 2 with various Cu/Ti ratios were prepared. CuO x /TiO 2 was prepared by incipient-wetness im-pregnation with aqueous solution of copper nitrate. Au catalysts were prepared by deposition-precipitation method at pH 7 and 338 K. The catalysts were characterized by inductively-coupled plasma-mass spectrometry, temperature programming reduction, X-ray diffraction, transmission electron microscopy, high-resolution transmission electron mi-croscopy and X-ray photoelectron spectroscopy. The reaction was carried out in a fixed bed reactor with a feed containing 1% CO in air at WHSV of 120,000 mL/h·g. High gold dispersion and narrow size distribution was obtained. The addition of CuO x in Au/TiO 2 enhanced the activity on CO oxidation significantly. CuO x was in amorphous state which could stabilize the Au nanoparticles. Cu was in Cu 1+ state. Cu donated partial electrons to Au. The interactions among Au, Cu 1+ and TiO 2 account for the high catalytic activity for CO oxidation. The significant promotional effect of CuO x on CO oxidation at low temperature was demonstrated.