CRF researchers Nils Hansen, Emma Litzer, and David Osborn, together with colleagues Wenqi Zhou, Alexander R. Morey, Carey Chang and Coleman X. Kronawitter from UC Davis, published a paper on “Transient Pulse-Response Time-of-Flight Mass Spectrometry for Complex, Deactivating Heterogeneous Catalytic Systems: Application to Ethane Dehydroaromatization” in “The Journal of Physical Chemistry C”.
In this work, the authors describe a time-resolved approach to measure the complete chemical composition of a catalytic reactor effluent (≈4–200 u) in response to controlled reactant pulses—providing kinetic and mechanistic information that complements traditional steady-state studies. The method uses a six-port rotary valve with a metered sampling loop to inject pulses at ambient pressure into a flow reactor containing a catalyst bed in the isothermal zone of a heated furnace. Effluent species are then tracked in real time with molecular-beam time-of-flight mass spectrometry, paired with energy-tunable ionization to improve isomer/isobar discrimination and enable collection of the full, time-dependent mass spectral response. They demonstrate the capability by probing the complex bifunctional chemistry of ethane dehydroaromatization over a Pt/HZSM-5 catalyst. Measurements capture the temporal evolution of major products and important intermediates. Additional studies with ethane and ethylene feeds clarify platinum’s role and reveal two temporally distinct formation pathways for methane and benzene. The time-resolved spectra also provide clear signatures of catalyst deactivation, including selective loss of a benzene formation pathway.
For more details visit: https://doi.org/10.1021/acs.jpcc.5c08401