Infrared spectroscopy in time and space

Research Project, 2020 – 2023

Fast infrared spectroscopy (IRS) will be adapted for probing sites and chemical interactions in (nano)confined spaces on time scales ranging from milli- to nanoseconds. To reach milli-, micro- and nanosecond time resolution, three different trigger methods will be used that relates to injected gas pulse, sensitive temperature control and laser stimulation, respectively. The experimental system will operate at pressures from 1 to 30 atm and at temperatures from ambient to 800 °C, with a future extension towards liquid nitrogen temperatures. Microporous materials commonly used for purification, separation and catalysis are main targets. The aims include to make millisecond linear IRS in step-scan mode an established practice for characterisation of microporous materials and solid materials generally and develop nanosecond linear IRS in step-scan mode for characterisation site dynamics via adsorption-desorption of chemical probes and reactants. Two scientific cases based on industrially relevant processes will be studied. The first is formation and decomposition of methoxy species in the direct conversion of methane to methanol over ion-exchanged zeolites and the second is to elucidate confinement effects on selective reduction of nitrogen oxides with ammonia over vanadia contained in microporous titania. The possibilities and challenges with nonlinear (2D) IRS for bond specific structural resolution of confined chemical reactions on relevant time scales will be explored.