In situ infrared approach to unravel reaction intermediates and pathways on catalyst surfaces

Abstract

Reaction intermediates on catalyst surfaces have often been elucidated on the basis of ex situ observation of adsorbed species and theoretical computations because of the difficulty in carrying out in situ studies, and the elusive nature of the intermediates under reaction conditions. In the past few decades, we have developed an in situ infrared spectroscopic method coupled with mass spectrometry (IR/MS setup) for investigating reaction intermediates for a number of catalytic reactions: CO/H2, CO/H2/C2H4, NO/CO, NO decomposition, CO2/CH3OH, and photocatalytic reactions. This review presents the key features of using an IR/MS experimental setup to perform transient studies. Transient studies involve perturbing the reaction system and monitoring the responses. This review highlights the usefulness of transient response data to unravel the reaction intermediates and pathways.