THE RELATIONSHIP BETWEEN THE STRUCTURE AND ACTIVITY OF NANOMETER-SIZEGOLD WHEN SUPPORTED ON MG(OH)(2)

In the following paper catalysts of Au supported on Mg(OH)(2) were ana lyzed by extended X-ray absorption fine structure spectroscopy and Deb ye function analysis. From these studies only catalysts with Au-size d istributions below 1 mm in size were found to be active for CO oxidati on. Below 1 Mn in size the gold exists in two forms; icosahedral and f ee cuboctahedral. Comparison of turnover frequencies for catalysts pre pared with different ratios of the two symmetries suggest that the ico sahedral symmetry is the more active form. Above 1 mm in size the gold takes either FCC cuboctahedral or decahedral symmetry. These results suggest that oxidation of CO over the Au/Mg(OH)(2) catalyst is structu re-dependent and that care must be taken in comparing results, where n o structural information is available. (C) 1998 Academic Press.