Synergetic Catalysis Of NiO_x With Oxygen Vacancies And Ni₂P For HDO Of Phenolic Compounds

With uncreasingly consuming of petroleum,environmental pollution is also gradually severe.Pursuing clean alternative energy has been an essential issue for humankind.So the biomass energy has attracted significant attention in the world.Biomass fuels are considered as great petroleum substituting energy source because of the availability of biomass in countries with no fossil fuels,their low sulfur and metal content.High efficient hydrodeoxygenation of oxygenated chemicals at low temperature is a critical issue for biomass crude oil upgrading to reduce equipment and operation expenses.Unique electronic features of oxygen vacancies have been found to facilitate occurrence of deoxygenation above 250?.In this work,firstly a series of NiO,/SiO₂ catalysts containing some oxygen vacancies were prepared by sol-gel and controllable temperature-programmed reduction method.Results show that NiOx/SiO₂ has superior phenol hydrogenation activity to deoxygenation even at 180?,which was contrary to Ni₂P/SiO₂.High hydrogenation activity derives from flat adsorption of phenolics over low valence Ni cations induced by connected oxygen vacancies.As introducing NiOx into Ni₂P catalysts,composite NiOx-Ni₂P/SiO₂ bifunctional catalysts demonstrate excellent phenol HDO performances under mild reaction conditions in comparison with individual Ni₂P and NiOx catalysts and most of results from literatures because the coexistence of oxygen vacancies from NiO,and acid induced by Ni₂P results in synergistic effect of adsorption configuration and hydrodeoxygenation ability,Besides,this composite catalyst also has a high activity for hydrodeoxygenation of different bio-derived cresol isomers.The reuse test result confirms that oxygen vacancies are relatively stable in comparison with phosphide.