Deactivation of Pt catalysts during wet oxidation of phenol

Removal of phenol by wet air oxidation was conducted with 1 wt.% Pt/Al2O3 and 1 wt.% Pt/CeO2 catalysts. During the reaction carbonaceous materials were formed and deposited on the catalyst surface, and the materials deactivated the catalysts. XPS analysis showed that the carbonaceous materials on the Pt/Al2O3 catalyst were composed of four different morphologies. As the wet oxidation proceeded, C2 type and C3 type carbonaceous materials transformed into C4 material. In the Pt/CeO2 catalysts, however, C4 material was not formed through the reaction. The broad profiles of CO2 formation from TPO experiment implied that there were at least two types of carbon deposits burning at different temperatures; one on Pt particles, the other Al2O3 and CeO2. The primarily formed carbonaceous deposit on Pt particles migrated continuously onto the supports.