IN-SITU STUDY BY XAS OF THE SULFURATION OF THE PT AND PTRE AL2O3 SYSTEMS/

We follow the structural evolution of industrial catalysts, Pt and PtR e deposited on alumina, during the in situ sulfuration steps of the ac tivation procedure using EXAFS spectroscopy. For the monometallic, we measure a large amount of sulfur (3S/Pt), as well as a decrease in pla tinum bonds (4.5 to 1.5). For the bimetallic, the number of sulfur ato ms in the vicinity of platinum still significant (1S/Pt), sulfur atoms being preferentially adsorbed on rhenium (2S/Re). During the sulfurat ion treatment, the numbers of platinum-metal and rhenium-metal bonds s tay constant.