Unsupported Sulfided Catalyst Prepared By Hydrothermal Synthesis For The Hydrodeoxygenation

China’s economy is in a stage of rapid development, where needs more and more energy. But the traditional fossil energy reserves is declining, and its utilization has brought many environmental problems. Developing a new renewable green environmental-friendly resource is already in the extremely urgency. Bio-oil is a liquid fuel from the fast pyrolysis of biomass(wood, straw, etc.) under the conditions of isolated from oxygen and medium temperature(500~600 ℃). It has attracted a lot of attentions because of its properties of abundance, easy to transport, renewable and high energy density. However, this lignocellulosic-derived bio-oil contains a considerable amount of oxygenated compounds, resulting in some defects such as thermal instability, corrosion, low-heat value, incompatibility with conventional fuels,and high viscosity, which hinders its wide utilization as fuel. For cost-effective use of bio-oil, it should be refined by hydrodeoxygenation to decrease its oxygen content.The unsupported MoS2 nanocatalysts have good HDO catalytic activity. Its morphology depends on their preparation method, which also determine its catalytic activity. This paper focuses on how to improve the HDO catalytic activity of MoS2.The detail researches are showed as followings: ① MoS2 catalyst: The unsupported MoS2 nanocatalysts with the addition of surfactant were prepared by hydrothermal method. The results displayed that adding surfactant significantly increased the specific surface area of the catalyst, changed the stacking layers of the catalyst surface.In the HDO of p-cresol, direct deoxygenation and hydrogenation-deoxygenation depended on the stacking layers. The active sites of the Mo-S catalyst could be explained by the Rim-Edge model. When adding DBS, the stacking layers decreased,increased the selectivity of methylcyclohexane. Adding PVP could increase the stacking layers and then increased the selectivity of toluene. The reaction mechanism on these catalysts’ surface was also deduced. ②Co-Mo-S catalyst: It had reported that adding Co could improve the activity of MoS2 catalyst. Hence, we adopted one step hydrothermal method to prepared Co-Mo-S catalysts and focused on the influence of temperature and the molar ratio of Co-Mo on the catalysts’ HDO activity.The results showed that the optimal reaction temperature for the preparation of Co-Mo-S catalyst was 200 °C. With the increase of Co content, the number of layers in the stack increased first and then decreased, while the slab length decreased first and then increased. The conversion of p-cresol on Co-Mo-S was high to 100% with adeoxygenation degree of 100% and a HYD/DDO of 0.08 at 275 °C for 4 h. ③Ni-W-Mo-S catalyst : Because of the synergy between the W and Mo, we also prepared unsupported Ni-Mo-W sulfide catalysts by one step hydrothermal method.Adjusting the W/Mo molar ratio in Ni-Mo-W-S can promote the dispersion of the active phases, leading to a high number of active site and shorten the slab length of MoS2 structure, which produced a high proportion of corner site. Among these catalyst, W-Mo-0.5 exhibited the highest activity in the HDO of p-cresol. The conversion was high to 97.9% with a deoxygenation rate of 97.56% at 300 °C for 4 h.