Selective NO-H_2-O_2 Reactions over Pt/TiO_2-ZrO_2 at<100°C

摘要

Platinum supported on TiO_2-ZrO_2 was found to be a highly active catalyst for 0.08% NO-0.28% H_2 reaction in an excess (10%) O_2 at <100°C. Kinetic analysis, comparison with H_2-O_2 reaction and in situ DRIFTS measurement revealed that the oxidative NO adsorption yields NO_3/NO_2 adsorbed on the surface of Pt and the support. These oxidized intermediates monopolize the Pt surface and thus severely limit the H_2-O_2 combustion at lower temperatures. This is a possible reason for the selective NO reduction and negligible inhibition from coexisting O_2. The different activity of oxidized and reduced catalysts is explained by the stability of the oxidative intermediates.