At supersonic speeds the aerodynamic heating can cause a significant increase in the temperature of the engine and other components of the aircraft. One of the strategies for active cooling of the components is to adsorb the energy excess by driving the endothermic reactions within the fuel. Dehydrogenation and cracking are the endothermic reactions well known to occur in hydrogen fuels, but both can lead to formation of undesired carbon coke precursors that clogs the fuel systems and causes engine failures. The efficiency and performance of these reactions however, can be significantly improved by the use of catalysts that can not only lower the reaction temperature, but also change the reaction pathways. Among the factors that can effect catalyst selectivity and performance are composition, particle size and the support-catalyst interactions. Understanding the mechanisms that affect activity and selectivity of catalysts suitable for endothermic fuel cooling is of critical importance for the advancement of the field.  Here we combine in operando synchrotron-based small angle X-ray scattering (SAXS) and X-ray Absorption Near-Edge Structure (XANES) measurements to gain valuable insights into catalyst stability and reaction state in realistic temperature and pressure conditions. In addition, reaction products recovered at various stages of the reaction have been analyzed gas chromatography�mass spectrometryGC-MS with the focus on the detection of coke precursor species. Methodical screening of different types of catalysts on a range of supports can help to identify the most optimal catalyst-support combinations with the most desirable stability/reactivity characteristics.

In situ X-ray scattering studies of high temperature and pressure catalysis for high performance scram jet engines

248th National Meeting (2014)

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