Supported gold catalysts prepared from a gold phosphine precursor and As-precipitated metal-hydroxide precursors: Effect of preparation conditions onthe catalytic performance

Supported gold catalysts highly active for low-temperature CO oxidation wer e prepared by using AuPPh3NO3 complex as a Au-metal precursor and wet as-pr ecipitated iron hydroxide and titanium hydroxide as support precursors. Eff ects of catalyst preparation conditions on the performance for low-temperat ure CO oxidation were studied. Metal-hydroxide precipitation conditions and heating rates of temperature-programmed calcination altered significantly the performance of the supported gold catalysts. To elucidate key factors r esponsible for the effects the catalysts were characterized by EXAFS, TEM, XRD, and N-2 adsorption. Changes in the activities of both Au/Fe oxide and Au/Ti oxide catalysts originated mainly from changes of the Au particle siz e distribution. It was also found that states of the mesoporous support pre cursors upon attaching the An precursor onto them and during the temperatur e-programmed calcination appeared to be of great importance in obtaining di spersed Au nanoparticles on oxide surfaces. (C) 2000 Academic Press.