Temporal analysis of products (TAP) study of the adsorption of CO, O2, and CO2 on a Au/Ti(OH)4* catalyst

The adsorption kinetics on Au/Ti(OH)(4)* (a newly developed Au catalyst, active for low-temperature CO oxidation) for CO, O-2, and CO2 in the temperature range 298-473 K was determined by temporal analysis of products (TAP) technique. The response signals from the single-pulse TAP experiments were analyzed using a statistical approach, and they were fitted to analytical models in order to establish the adsorption/desorption parameters. The pulse response of a non-adsorbing gas (argon) was used as a reference. The experiments revealed that: CO molecules reversibly adsorbed on the catalyst surface; O-2 molecularly adsorbed, irreversibly for high pulse intensities and reversibly for low pulse ones; CO2 molecules irreversibly adsorbed on the surface, probably as carbonates. This catalyst exhibited an apparent negative activation energy for irreversible adsorption of O-2.