Speaker: Grigory Smolentsev, PSI
Program Description:
First, I will overview the development of time-resolved X-ray absorption spectroscopy at SuperXAS beamline of the SLS synchrotron in the time range from nanoseconds to milliseconds. The pump-sequential-probes setup (Smolentsev et al Faraday Discuss. 171 (2014) 259) is an essential part of our portfolio of techniques. It allows the measurements of weak differential signals from diluted samples and it is optimized to study photocatalysts. Then I will show how different steps of the photocatalytic reaction of H2 production have been studied. The structure of Co(I) intermediate formed as a result of the charge transfer from the photosensitizer to the cobalt-based catalyst has been determined from the quantitative analysis of time-resolved XANES spectra. Finally, I will demonstrate how protonation of the catalytic center has been investigated for the full photocatalytic system. The review of our other time-resolved XAS results in the field of artificial photosynthesis can be found in (G. Smolentsev, V. Sundström Coord. Chem. Rev. 304-305 (2015) 117).
