Fundamental Studies on Catalyst Deactivation and Corrosion Phenomena under Biomass Feed and the Interaction with Polar Biomass-Derived Molecules

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The conversion and valorization of biomass and biomass-derived raw materials is of major importance for the future sustainable supply of energy and basic chemicals, especially with regard to the continuously shrinking crude oil, natural gas and coal resources. In contrast to petrochemical reactions, catalytic conversion of biomass often proceeds in the liquid phase, due to the polarity of these molecules. The interaction of polar molecules with heterogeneous catalyst surfaces in the liquid phase will be studied in order to gain more insight into the molecular processes that lead to catalyst corrosion and deactivation. Important deactivation pathways are leaching of the active phase and the support, particle sintering, poisoning by strong adsorbing reaction intermediates and products as well as the formation of coke and oligomeric species. These processes will be investigated on well-defined model catalysts, i.e. flat substrates with supported catalyst particles, which allow for advanced characterization by microscopic, optical and electronic spectroscopy methods, preferentially under in-situ or operando conditions. As reaction systems the conversions of glycerol, glucose, succinic and maleic acid as well as cellulose will be used as typical model systems, containing the prototype functional groups (i.e., ROH, HRC=O, R2C=O and RCOOH) for biomass related conversions.The molecular level understanding will be later transferred to industrially relevant reaction conditions applying supported catalyst particles in high pressure/high temperature reactors with operando spectroscopic analysis of the working catalysts. Based on the gained knowledge, new concepts for the stabilization of the applied catalysts will be developed.