Preparation Of Highly Dispersed RuCo-based Catalyst For Hydrodeoxygenation

Lignin is a major component of biomass resources.With the deepening of cognition of environmental pollution and resource depletion,lignin,as a kind of abundant renewable resource,has attracted much attention.The mixture can be catalytic hydrodeoxygenated to produce chemical platform molecules and fuels.Therefore,the research on catalytic hydrodeoxygenation of lignin has practical significance.In the current research,the traditional acidic oxide is used as a catalyst carrier,in which some of the catalysts have too low deoxidation rate,and the catalyst with high deoxidation rate needs to be carried out in a harsh high temperature and pressure environment.Therefore,it is worthwhile to develop a highly efficient catalyst for hydrodeoxygenation of lignin derivative under mild reaction conditions.Co3O4 is a carrier with oxygen vacancy,and the presence of oxygen vacancy is conducive to the adsorption of oxygen atoms,thus facilitating the generation of deoxygenation products.It is well known that Ru,which is relatively inexpensive in precious metals,exhibits excellent properties in the field of hydrodeoxygenation.In this paper,Ru and Co were combined to design and synthesize two different structures and high-efficiency catalysts for hydrodeoxygenation of lignin derivatives.The main work is as follows:1.In this paper,the ordered macroporous Co3O4 prepared by sacrificial hard template method was used as a carrier to load Ru by sodium borohydride reduction method,and the Ru/DOM-Co3O4 catalyst obtained is applied to the hydrodeoxygenation reaction of anisole.The bimetallic catalysts obtained herein have higher activity and deoxygenation product selectivity than Ru-based catalysts supported on other ordered macroporous oxides and commercial oxides.The selectivity of the complete deoxygenation product was 96.55%under the reaction conditions of 250? and 0.5 MPa.A highly active and selective hydrodeoxygenation catalyst was obtained under mild reaction conditions.The excellent catalytic performance is attributed to the strong adsorption capacity of the Co3O4 support to oxygen atoms,the high mass transfer rate brought by the ordered macroporous structure and the highly dispersed Ru nanoparticles.2.Highly dispersed Ru-doped Co-CoOx/C catalyst was prepared by hydrotalcite/carbon composite precursor method and applied to the hydrodeoxygenation reaction of guaiacol.The catalyst showed high activity for hydrodeoxygenation of guaiacol,and the selectivity of cyclohexanol reached 94.1%under the reaction conditions of 200? and 1 MPa.Cyclohexanol can be further reacted under reaction conditions of 260? and 2 MPa to obtain a large amount of cyclohexane.The addition of Ru changes the particle size of the Co species particles,regulates the oxygen vacancies on the surface and introducing strong hydrogenolysis activity sites.The results show that the reduction temperature affects the hydrodeoxygenation activity of the catalyst.Compared with 500? and 700?,the catalyst prepared by reduction at 600? exhibits higher hydrodeoxygenation activity.This is mainly because the high reduction temperature increases the degree of reduction of cobalt oxide and the surface oxygen deficiency sites;but at the same time,the dispersion of Ru and the ability to adsorb and dissociate hydrogen decreases.