Robin Vogel
Light olefins, such as propylene and ethylene are key building blocks in the chemical industry for the production of polymers, oxygenates and other chemical intermediates. Dehydrogenation of propane, facilitated by either platinum-tin or chromium oxide based catalysts is an industrial road towards propylene. During this process coking and subsequent activity loss of the catalyst occurs as the products of side reactions react with the olefin. The catalytic activity is regained in an oxidative regeneration step. [1]
Operando Raman spectroscopy has been used in this group to investigate the dynamics taking place within a dehydrogenation catalyst. Unfortunately, a strong fluorescence background overshadowed the Raman scattering during initial stages of hydrogenation and regeneration. [2] Raman scattering and fluorescence occur on a different timescale and can therefore be separated by measuring in a time-resolved manner with the aid of new commercial time-gated Raman spectroscopy instruments.
The aim of this study is to develop and explore time-gated Raman spectroscopy to gain more understanding in coke formation during successive dehydrogenation and regeneration cycles under industrial relevant conditions. In a second step, we strive to use shell-isolated nanoparticles enhanced Raman spectroscopy (SHINERS) to further increase the sensitivity of the Raman technique. The combined information obtained from both techniques offers direct means to define protocols for optimal regeneration of dehydrogenation catalysts.
[1] J. J. H. B. Sattler, J. Ruiz-Martinez, E. Santillan-Jimenez, and B. M. Weckhuysen, “Catalytic dehydrogenation of light alkanes on metals and metal oxides,” Chem. Rev., vol. 114, no. 20, pp. 10613–10653, 2014
[2] J. J. H. B. Sattler, A. M. Beale, and B. M. Weckhuysen, “Operando Raman spectroscopy study on the deactivation of Pt/Al 2O3 and Pt-Sn/Al2O3 propane dehydrogenation catalysts,” Phys. Chem. Chem. Phys., vol. 15, no. 29, pp. 12095–12103, 2013