Fischer-Tropsch Synthesis on Bimetallic Ruthenium-Gold Catalysts

The effect of Au in the behavior of Ru as a Fischer-Tropsch catalyst was studied. Two series of catalysts were investigated, one supported on Si02 and the other on MgO. Au did not seem to alter the product distribution on Ru at pressures up to 1 MPa and in the temperature range 490-570 K. However, the turnover frequencies for both CO hydrogenation and methanation showed a precipitous drop with the Au content in the Si02-supported catalysts, whereas on the MgO series a maximum in activity was observed at an intermediate Au content. These activity patterns were correlated with extensive physical characterization placing major emphasis on analytical electron microscopy. The activity trends as a function of Au content were remarkably similar to those previously reported for the structure-sensitive ethane hydrogenolysis reaction. In both reactions, the effect of Au appears to be due to a dilution of the active Ru ensembles. o 1985 Academic PKSS, I~C.