The in-situ formation of supported hydrous ruthenium oxide in aqueous phase during HDO of lignin-derived fractions

The in-situ formation of supported hydrous ruthenium oxide (HRO) from RuO2 over micro-mesoporous materials is reported for the selective hydrogenation of bio-oil under mild reaction conditions (200 °C, 20 bar H2) in an aqueous medium. For the first time, the phase composition of HRO was determined using a variety of characterization techniques. Using synchrotron radiation and in-situ X-ray absorption spectroscopy (XAS), we demonstrated that HRO was generated during the hydrodeoxygenation process. The hydrodeoxygenation (HDO) of real bio-oil was successfully performed at 200 °C, 20 bar H2 on RuO2-containing catalysts. The approximate composition of HRO after 3 h of catalytic hydrogenation, consisted of in approximately equal ratios metallic Ru, RuO2, and RuOOH phases.