Unsupported Sulfided Mo-based Catalyst Prepared By Hydrothermal Synthesis For The Hydrodeoxygenation

With the development of world economy, fossil resources like oil, coal and naturalgas will dry up day by day. For over a century, thousands of scientists have been devotingto the development of alternative energy sources to solve the problems in energy securityand environmental protection. Many researches prove that: biomass obtain the mostattention in renewable energy alternative schemes because of its common existence andlow cost. Bio-oil is usually produced by biomass through high temperature rapid crackingor high voltage direct liquefaction. In bio-oil, the oxygen content is too high, and evensome oxygen mass fraction reaches as high as50%, as a result, leads to low combustionvalue, high viscosity, miscibility, easy corrosion, and bad thermal and chemicalstability.Thus having a serious impediment to the wide application of bio-oil. In order toefficiently remove oxygen compound in bio-oil, we made a series of TiO₂-Al₂O₃composite supports and Mo based sulfide nanosize particles by co-precipitation andHydrothermal methods.The products were characterized by means of XRD、BET、SEMand TEM. The catalytic activities were tested by using4-methyphenol as modeloxygen-containing compound.The activity of the catalyst can get improved by the improvement of the carrier.Therefore, in most literatures, Al₂O₃is researched as the carrier in hydrodeoxygenationcatalyst. However, the researches on TiO₂-Al₂O₃acting as a carrier in hydrodeoxygenationcatalyst are very few. Therefore, TiO₂-Al₂O₃composite supports were synthesized fromAlCl3and NH4HCO3（or NH3·H2O and （NH）2CO） as the precipitant by co-precipitationmethod combined with ultrasonic dispersion. The effects of precipitants on the propertiesof TiO₂-Al₂O₃composite supports were studied. The results show that: TiO₂in TiO₂-Al₂O₃composite supports were anatase phase, Al₂O₃were existence of γ-Al₂O₃, and improvedthe thermal stability of anatase phase, added CTAB conducive to increase of pore diameterand pore volume. Among three precipitants, the support precipitated using NH4HCO3solution had the best structure performance, it is because NH4HCO3is a buffer solutionwhich releasing NH4+with a slowly speed. The pore diameter of TiO₂–Al₂O₃compositesupports was30.9nm; pore volume was2.19mL/g; specific surface area was284m2/g.In view of sulfide catalyst is the most typical hydrogenation catalyst. We prepared aseries of Mo-S、Co-Mo-S、Co-Ni-Mo-S Mo based sulfide catalysts by hydrothermalsynthesis. These catalysts were applied into the hydrodeoxygenation of4-methyphenol. The effects of active components mole ratio and reaction temperature were optimized. Thegrowth of MoS2crystallized particles was inhibited when Ni or Co was incorporated.Addition of Co or Ni promoter decreased Mo-S surface area. Compared with Mo-S, TEMand XRD results showed that addition of Co and or Ni to the unsupported Mo sulfidecatalyst affected the chemical（such as edge decoration） and structural （such as textural ormorphological） characteristics of the catalyst. These unsupported Co-Mo-S Mo basedsulfide catalysts were favoring DDO pathway, however, Co-Mo-S were favoring HYDpathway.