The effect of niobia on the methanation activity of a Pt foil

Abstract

Recent work examining the interaction between titania and transition metals has indicated that a partially reduced titania overlayer can form on the surface of a titania-supported catalyst. In addition, the authors have shown that a Pt foil with a titania overlayer exhibits the same methanation rates as are reported for actual titania-supported Pt catalysts, even though complete suppression of CO and H/sub 2/ adsorption is observed. Unusual support effects are observed for metals on niobia as well. As with titania-supported catalysts, catalysts supported on niobia can exhibit suppressed adsorption of CO and H/sub 2/ while maintaining a high methanation activity. To determine whether an overlayer of niobia was responsible for the properties observed with niobia-supported catalysts, the authors have examined the methanation activity for a Pt foil with a niobia overlayer. The experimental apparatus consists of a sample attached to a magnetically manipulated, linear-motion feedthrough which can be isolated from an ultrahigh vacuum system. This system allows them to measure reaction rates at atmospheric pressures on a sample which can be characterized by Auger electron spectroscopy (AES) both before and after reaction. This system is described in more detail elsewhere. 22 references.