A single-turnover (STO) study of the effect of heat on catalyst activity

Abstract

Single-turnover (STO) site characterizations have been run on a number of Pt/CPG (controlled pore glass) catalysts both before and after being heated in H₂, He and O₂. Catalyst deactivation was observed on heating at temperatures as low as 250 °C in either H₂ or He with activity restored on exposure to O₂ either at elevated temperatures for short times or under ambient conditions for long periods of time. The results obtained show that the only factor involved in the deactivation is the heat, so the loss of activity is considered to result from a reorganization of surface atoms into less active arrangements. Exposure to O₂ would then cause a restructuring to a more active surface. Some data indicate that when these treatments are not too severe the O₂ exposure regenerates essentially the same surface characteristics the catalyst had before heating.