Improved H 2-D 2 exchange activity of Pt and Pd by UHV treatment

Abstract

The activity of polycrystalline Pt and Pd catalysts for the H 2-D 2 exchange reaction was enhanced by heating them at temperatures higher than 673 K at 10 -7 Pa for several hours. The exposure of a catalyst thus treated to air at room temperature had no effect on the enhanced activity. Therefore, the enhanced activity cannot be ascribed to the desorption of contaminant species by UHV treatment at high temperature; it may be caused by surface rearrangement. The XRD patterns of the UHV-treated catalyst indicated a slight enrichment of the (311) high-index face and the (200), (220) and (222) faces. The so-called step and/or kink structure may be responsible for the UHV-induced enhancement.