All chemical reactions are controlled by species we rarely detect: short-lived carbenes, radicals, and ketenes steer reaction pathways and ultimately determine selectivity and yield. Conventional tools such as GC/MS or NMR usually miss intermediates, even though mechanistic insight is urgently needed for rational process optimization.
In this seminar, I introduce operando Photoelectron Photoion Coincidence (PEPICO) spectroscopy with vacuum ultraviolet (VUV) synchrotron radiation at the Swiss Light Source as a multiplexed approach to reaction analysis. By detecting both ions and electrons after VUV ionization, PEPICO connects mass spectrometry with isomer-selective photoelectron fingerprints, allowing us to disentangle complex reaction mixtures.
I will illustrate how this approach changes our mechanistic understanding in heterogeneous catalysis and high-temperature chemistry, including zeolite-catalyzed plastic pyrolysis, where we identify mechanistic routes to benzene, toluene, and xylenes. Moreover, we turn to biomass conversion, where transient ketenes are the unwelcome guests that steer selectivity off-target.
I will leave you with a practical sense of what intermediates we can observe, how spectra are interpreted, and where operando detection can unveil new mechanistic insights.

The Department of Biochemistry invites professors and scientists from other universities and institutes to present seminars at the University of Colorado Boulder throughout the academic year. These seminars provide an opportunity for faculty and students to learn about exciting current research.

The Department of Biochemistry invites professors and scientists from other universities and institutes to present seminars at the University of Colorado Boulder throughout the academic year. These seminars provide an opportunity for faculty and students to learn about exciting current research.

The Department of Biochemistry invites professors and scientists from other universities and institutes to present seminars at the University of Colorado Boulder throughout the academic year. These seminars provide an opportunity for faculty and students to learn about exciting current research.