Conf. Plenaria: ATR-FTIR Spectrokinetic Investigation of Reactions at Solid-Liquid Interfaces

COLLINS, SEBASTIAN

Santa Fe

Conferencia; VI San Luis School and Conference on Surfaces, Interfaces and Catalysis; 2018

INTEC-UNL-CONICET

Attenuated total reflection (ATR) infrared (IR) spectroscopy is a powerful tool to investigate reaction pathways in liquid(reactive)/solid(catalyst) systems, because it provides the detection of adsorbed species on a catalyst under reaction conditions. Catalysts are commonly deposited on an internal reflection elements (IRE) as layers of powders or as films (e.g. metal film), and they are exposed to the liquid phase reactants. In order to study the evolution of adsorbed intermediates, transient techniques are usually applied, such as stop-flow and concentration-modulation excitation spectroscopy (c-MES). However, to obtain quantitative information, that is, determining intrinsic reaction rates, the chemical engineering aspects of an ATR flow-through cell must be developed. Particularly, mass transport into the ATR cell has to be characterized. We have developed an optimized flow-through ATR microfluidic cell to assess intrinsic kinetic parameters of reactions under chemical control. This ATR cell possesses no dead-volume and has a uniform fluid velocity profile across the cell. The mass transport dynamic from the bulk solution to the surface of the ATR crystal -where the catalyst is deposited- is described by a convection-diffusion transport model.