An Extended X-ray Absorption Fine Structure Spectroscopy Study of a Highly Dispersed Rhodium/Aluminum Oxide Catalyst: The Influence of Carbon Monoxide Chemisorption on the Topology of Rhodium

Abstract

The X-ray absorption spectrum of the Rh K edge of a highly dispersed reduced 0.57 wt % Rh/ y-A1203 catalyst shows EXAFS oscillations due to rhodium-rhodium nearest neighbors, which proves the existence of rhodium metal crystallites. Adsorption of CO at room temperature on the reduced catalyst significantly decreases the amplitude of these EXAFS oscillations. This implies that CO adsorption on very small rhodium crystallites leads to a disruption of a significant number of the metal-metal bonds.