INTEC   05402
INSTITUTO DE DESARROLLO TECNOLOGICO PARA LA INDUSTRIA QUIMICA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Identification of key reaction intermediates during toluene combustion on Pd/CeO2 using operando modulation DRIFT spectroscopy
Autor/es:
ALINE VILLARREAL; ALEJO AGUIRRE; SANTIAGO ROJAS; ESTEBAN L. FORNERO; SEBASTIAN E. COLLINS
Reunión:
Congreso; Operando Characterization of Catalysts at Work (OperCat); 2020
Resumen:
Toluene oxidation on CeO2 and Pd/CeO2 was investigated by operando DRIFT-MS. An optimized DRIFT cell, which behaves as a true plug flow microreactor, was employed. Concentration-modulation excitation spectroscopy (c-MES) experiments with phase sensitive detection (PSD) analysis were performed. Identification of active surface species under reaction conditions obtained by combining MES-PSD spectra with chemometric resolution of highly overlapped bands using a multivariate curve resolution-alternating least squares (MCR-ALS) method. A mechanism is proposed where toluene molecules preferentially adsorbed parallel to the surface via -bonding with the ceria surface. The methyl group is firstly activated by subtraction of an H atom, probably by interaction with O2- or HO-, forming a benzyl species intermediate. Stepwise oxidation, producing benzyl alcohol, benzaldehyde and benzoate was observed. Formate and aldehyde-like species are also identified, which can be produced by decarboxylation of benzoate or as a final product of the oxidation of the aromatic ring.