SEM and RHEED-REM study of au particles deposited on rutile TiO2 (110) by deposition precipitation and gas-phase grafting methods

In order to investigate the structural features of Au/TiO2 catalysts, which are active for the low-temperature oxidation of CO and reverse water shift reaction, a model structure was prepared by deposition precipitation (DP) and gas-phase grafting (GG) methods using rutile TiO2 single-crystal fragments with cleaved (110) faces. SEM (scanning electron microscope) and RHEED-REM (reflection high-energy electron diffraction-reflection electron microscope) observations proved that Au particles deposited by DP are nonhomogeneously dispersed while those by GG are homogeneously dispersed on the (110) surface of the rutile TiO2. The RHEED pattern indicated that a preferred orientation between the Au particles and the TiO2(110) was [(1) over bar 10](111)(Au)//[001](110)(TiO2) for both preparation cases. (C) 2002 Elsevier Science (USA).