INVESTIGADORES
BERLI Claudio Luis Alberto
congresos y reuniones científicas
Título:
Design and optimization of a flow-through ATR-FTIR cell for transient and modulated operando experiments
Autor/es:
ALEJO AGUIRRE, PABLO KLER, CLAUDIO BERLI, SEBASTIÁN COLLINS
Lugar:
Upton, New York, USA
Reunión:
Congreso; The 4th International conference on Operando Spectroscopy; 2012
Institución organizadora:
Brookhaven National Laboratory
Resumen:
Attenuated total reflection (ATR) infrared (IR)
spectroscopy is a powerful tool for the investigation of reaction pathways in
solid(catalyst)/liquid(reactive) systems, because it provides the detection of
species adsorbed on a catalyst under reaction conditions. However, the presence
of strongly absorbent solvents, spectator species and/or the catalyst itself
can make very difficult or preclude the identification and tracking of the true
active species, that is, the reaction intermediates. Then, transient
experiments are widely applied in the analysis of reaction intermediates by
perturbing a catalytic system working under steady state conditions (ss). More
recently, modulation excitation spectroscopy (MES) with phase sensitive
detection (PSD) have proved to be an adequate methodology to separate a weak
response from a strong background signal. MES experiments are based on the
disturbance of a ss system by the periodical variation of an external parameter
such as the temperature, the pressure, or the concentration of a reactant. Therefore,
all the species in the system that are affected by this parameter will also
change periodically with the same frequency of the perturbation, but with a
phase lag. Thus, MES, coupled with PSD analysis, applied to in situ ATR-IR
experiments can allow the sensitive and selective detection of species directly
involved in a reaction at the liquid/solid interface, and the monitoring of
their dynamic behaviors. In this work we present an optimized design of a
flow-through ATR cell for transient and operando-modulated experiments in the
solid-liquid interface. Examples of application are also shown.