Construction Of Highly Efficent And Stable Co-based Bimetallic Catalyst Based On MOFs And Its Catalytic Hydrodeoxygenation Performance

Currently,fossil source is playing a crucial role in the rapid development of industrial civilization.However,the excess consumption of fossil resources has brought many environmental problems.In order to solve this problem,renewable biomass sources are attracting more and more attention,because they can be converted into chemicals and high value-added bio-oils through various upgrading approaches.Take biomass-derived vanillin as an example,it contains benzene ring structure,high carbon content,aldehyde and methoxy group.Through hydrodeoxygenation(HDO)process,vanillin can be reduced into deoxygenated products with low oxygen content and high H/C value,which can be utilized as essential components of petroleum-like fuels and important chemicals.At present,a variety of noble metal catalysts have been explored in the HDO of biomass-derived phenolic compounds.Despite good hydrogenation performance of noble metal catalysts,their high cost and easy deactivation limit the practical applications of these catalysts.Therefore,non-noble metal catalysts,such cobalt,nickel and other elements,have been investigated to replace noble metal catalysts,due to their good hydrogenation performance.However,non-noble metal catalysts have several disadvantages including poor catalytic HDO activity and harsh reaction conditions.Therefore,it is challenging to design high-performance and stable non-noble metal catalysts for the HDO of biomass derivates.Based on the above research background,this study designed a high-stability bimetallic catalyst with excellent hydrogenation performance based on the MOF structure.The reaction mechanism of the catalyst for the hydrodeoxygenation of vanillin was studied.The main work is as follows:(1)Take Co-based MOFs material ZIF-67 as template,a carbon-coated nickel-cobalt bimetallic catalyst with high stability was constructed by introducing nickel,glucose hydrothermal and other ’experimental procedures.The performance of the catalysts with different ratios of nickel introduced was tested,and the optimal ratio of nickel to cobalt and the most suitable reaction conditions were determined.Under the conditions of 170℃ and 1 MPa H2,the catalytic vanillin can be completely converted to 2Methoxy-4-methylphenol.After many cycles,the performance of the catalyst remains stable.(2)Using ZIF-67 as a precursor to construct RuCo bimetallic hydrodeoxygenation catalyst.It was used to catalyze the hydrodeoxygenation of vanillin.The yield of 4-methylcycloheexanol can reach 100%under the reaction conditions of 250℃ and 2.0 MPa H2.The performance gap between monometallic ruthenium and monometallic cobalt and ruthenium-cobalt bimetallic catalysts was compared,and the reasons were explored.Due to the electron transfer between ruthenium and cobalt bimetals,it has more excellent hydrogenation performance,and it still has good hydrogenation performance after many cycles of experiments.