ABSTRACT Hydrodeoxygenation (HDO) of bio‐oils derived from lignin pyrolysis is a potential source of aromatic‐rich hydrocarbons for renewable jet fuels. MoO 3 catalyzes this reaction with high selectivity for aromatics, but deactivates at the high temperatures necessary for the reaction. Adding a noble metal, such as Ru, to MoO 3 could allow these catalysts to operate at much lower temperatures, since hydrogen spillover from Ru to MoO 3 forms potential active sites (oxygen vacancies and Mo–OH) at lower temperatures. We synthesize various MoO 3 samples with different crystal structures and surface areas, impregnate them with Ru, and use them as catalysts for the HDO of phenol (a model lignin derivative). Mo K‐edge XANES and OH titrations allow us to quantify the amount of hydrogen spillover that occurs during activation and compare this to the catalytic reactivity. Catalysts with more acid sites (derived from the hydrogen spillover) have higher conversions and higher selectivities for deoxygenated products, giving up to 54% at 300°C with up to 90% deoxygenation and 20%–30% benzene selectivity. The acid sites likely catalyze both the keto–enol tautomerization of phenol (thought to be responsible for HDO) and the deoxygenation of aliphatic products.
Turan et al. (Sun,) studied this question.