Catalytic conversion of lignin-based biomass to fuels and chemicals is of importance for the sustainable development of our society. Phenol has the simplest representative structure of phenolic compounds and has been widely used as a model compound for lignin-based biomass in the study of hydrogenation and hydrodeoxygenation of lignin-derived compounds to produce fuels and chemicals. Among these researches the oxygen removal was considered to be the most difficult and rate-limiting step. To better understand the hydrodeoxygenation mechanism, we examined the elementary surface hydrogenation/dehydrogenation steps and deoxygenation steps. Based on energetics of the elementary steps from DFT calculations and microkinetic analysis, we mapped out the most favorable route in deoxygenation from six distinct reaction routes. In particular, we used the Electron Localization Function of the hydrogenation intermediates to evaluate the extent of the electron location in the aromatic ring on the subsequent hydrogenation and deoxygenation reactions. Our results showed that hydrogenating partially the benzene ring reduces electron delocalization and enhances the deoxgenation activity. The kinetic parameters from the DFT calculations were used in the microkinetic modeling. Our results supported a hydrogenation-deoxygenation-dehydrogenation as the major route of benzene formation.

Electron delocalization in aromatic ring on hydrodeoxgenation of phonel on Pt(111)

252nd National Meeting (2016)

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