Phenolic compounds present from the decomposition of lignin in biomass present a considerable upgrading challenge, both for the selective cleavage of C-O bonds and for preserving carbon contained in methoxy groups on the ring during the upgrading step while maintaining catalyst activity. While Ru/TiO2 catalysts demonstrate promise for catalyzing these reactions, the location and role of the active sites created by the metal and the reducible oxide are subject to debate. In this contribution, we vary independently the TiO2 phase as well as the metal perimeter and calculate the conversion rates associated with each type of possible active site. By comparing initial rates over 11 different catalysts with varying particle size and TiO2 support phase, we demonstrate the critical role of the oxide perimeter surrounding the metal nanoparticles on the direct HDO reaction upon converting cresol to toluene. We also show how compounds containing two OH groups such as catechol can be converted over various sites, including the reduced support sites away from the metal particle as demonstrated through in-situ titration experiments. The impact of each catalytic site is discussed, and a multisite kinetic model is presented for the conversion of phenolic species to aromatics.

Role of TiO2 defects and the Ru/TiO2 interface on the conversion of phenolics

249th National Meeting (2015)

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