ATR-FTIR Spectrokinetic Analysis of the CO Adsorption and Oxidation at Water/Platinum Interface

CLAUDIO BERLI; SEBASTIAN COLLINS; ALEJO AGUIRRE

CATALYSIS TODAY

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2017 vol. 283 p. 127 - 133

0920-5861

Attenuated totalreflection infrared (ATR-IR) spectroscopy is a powerful tool to investigatereaction pathways in liquid(reactive)/solid(catalyst) systems. Catalysts arecommonly deposited on an internal reflection elements (IRE) as layers ofpowders or as films (e.g. metal film), and they are exposed to the liquid phasereactants. To obtain quantitative information of intrinsic reaction rates, thechemical engineering aspects of an ATR flow-through cell must be evaluated.Particularly, mass transport in the ATR cell has to be characterized. Wepresent here an analysis of the mass transfer from the flowing solution to thesurface of the ATR crystal, where the catalyst is deposited. Criteria todetermine kinetic parameters under chemical control were developed on the baseof non-dimensional Péclet (Pe) andSherwood (Sh) numbers, and Thielemodulus (fcl). A Pt thin film deposited on a ZnSe IRE by vapordeposition and a layer of Pt/Al2O3 porous catalyst wereused to study the adsorption of carbon monoxide and oxidation of preadsorbedcarbon monoxide on aqueous phase. Experimental data of the evolution of the linearlyadsorbed CO (2048 cm-1) were fitted using a microkinetic model toobtain reaction constants. Results reported here serve as a practical guideto quickly determine the operational limits of an ATR cell with a porous layerof catalyst deposited onto the IRE.