Probing combustion and catalysis intermediates by synchrotron vacuum ultraviolet photoionization molecular-beam mass spectrometry: recent progress and future opportunities.

Soft photoionization molecular-beam mass spectrometry (PI-MBMS) using synchrotron vacuum ultraviolet (SVUV) light has been significantly developed and applied in various fields in recent decades. Particularly, the tunability of SVUV light enables two-dimensional measurements, mass spectrum and photoionization efficiency spectrum measurements, affording isomer distinguishment in complex reaction processes. Many key intermediates have been successfully detected in combustion and catalysis reactions with the help of the state-of-the-art SVUV-PI-MBMS, promoting the understanding of the chemical mechanisms. Herein, we present a brief review of the instrumentation of beamline and PI-MBMS machines at the current synchrotron user facility Hefei Light Source II and exemplify the advantages of the SVUV-PI-MBMS method with recent applications in combustion and catalysis research, especially in probing key reaction intermediates. Future opportunities with the next generation synchrotron light source and bench-top light source have also been discussed.