Effects of Au-Ce strong interactions on catalytic activity of Au/CeO2/3DOM Al2O3 catalyst for soot combustion under loose contact conditions

Au/3DOM (three-dimensionally ordered macroporous) Al2O3 and Au/CeO2/3DOM Al2O3 were prepared using a reduction-deposition method and characterized using scanning electron microscopy, N-2 adsorption-desorption, X-ray diffraction, transmission electron microscopy, ultraviolet-visible spectroscopy, temperature-programmed hydrogen reduction, and X-ray photoelectron spectroscopy. Au nanoparticles of similar sizes were well dispersed and supported on the inner walls of uniform macropores. The norminal Au loading is 2%. Al-Ce-O solid solution in CeO2/3DOM Al2O3 catalysts can be formed due to the incorporation of Al3+ ions into the ceria lattice, which causes the creation of extrinsic oxygen vacancies. The extrinsic oxygen vacancies improved the oxygen-transport properties. The strong metal-support interactions between Au and CeO2 increased the amount of active oxygen on the Au nanoparticle surfaces, and this promoted soot oxidation. The activities of the Au-based catalysts were higher than those of the supports (Al2O3 or CeO2/3DOM Al2O3) at low temperature. Au/CeO2/3DOM Al2O3 had the highest catalytic activity for soot combustion, with T-10, T-50, and T-90 values of 273, 364, and 412 degrees C, respectively. (C) 2016, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.