Fabrication And Catalytic Performance Of Perovskite Oxide For The Catalytic Hydrodeoxidation Of M-cresol

At present,our country has a shortage of energy,a single consumption structure,and a large dependence on oil imports.Changing the current energy consumption structure and developing energy diversification and renewable energy is an inevitable choice for national energy security.The large-scale development of biomass energy has become one of the research hotspots in the world’s scientific research community.Perovskite oxides can generate highly dispersed and stable metal centers and oxygen-philic centers during the reduction process,meeting the requirements of biomass oil hydrodeoxygenation.while increasing the pore structure of perovskite oxides and increasing the active surface area.Reduce the mass transfer resistance of the reaction process and reduce the retention of carbon deposit precursors on the catalyst surface,and inhibit the deactivation of the catalyst carbon deposit.In this paper,a series of perovskite oxide catalysts were prepared,and the hydrodeoxygenation reaction of m-cresol was used as a probe to investigate the influence of the preparation method,pore structure,reaction conditions and other factors on its catalytic performance.The reaction mechanism of the hydrodeoxygenation reaction of m-cresol was deduced by analysis.Increasing the pore size of the perovskite oxide can increase the active surface area,reduce the mass transfer resistance of the reaction process and reduce the retention of carbon precursors on the catalyst surface,and inhibit the deactivation of the catalyst by carbon deposition.In this paper,a series of perovskite oxide catalysts were prepared,and the hydrodeoxygenation reaction of m-cresol was used as a probe to investigate the influence of the preparation method,pore structure,reaction conditions and other factors on the catalytic performance of the catalyst.The reaction mechanism of the hydrodeoxygenation reaction of m-cresol was analyzed and deduced.La₂FeNiO₆ perovskite-type oxide catalysts were prepared by hydrothermal synthesis,co-precipitation and sol-gel methods,respectively.The La₂FeNiO₆ samples prepared by different preparation methods all have a complete perovskite-type oxide structure.The sample prepared by the sol-gel method has a loose surface structure,larger pore size and specific surface area,and can reduce more metal centers during the reduction process,and has better catalytic performance for the hydrodeoxygenation of m-cresol.Reaction temperature and hydrogen flow can affect the catalytic activity of La₂FeNiO₆ catalyst and the distribution of reaction products.Under the conditions of 375℃,0.32 h space-time and 20m L/min hydrogen flow,the conversion rate of m-cresol reaches 36.3%;toluene selectivity is 78.2%.The La₂FeNiO₆,LaFeO₃ and LaNiO₃ perovskite oxide catalyst samples were prepared by the sol-gel method,and the catalytic performance of the single perovskite oxide and double perovskite oxide samples were compared.The results show that the interaction between the B-site ions Fe and Ni in the La₂FeNiO₆ double perovskite-type oxide promotes the reduction of Ni,which can generate more metal centers and oxygen vacancies during the reduction process,and has better catalysis Hydrodeoxygenation performance of m-cresol.At the same time,the mechanism of the catalytic hydrodeoxygenation reaction of m-cresol was preliminarily discussed.On the La₂FeNiO₆ catalyst,due to the more oxygen vacancies（oxyphilic centers）on the surface,meta-cresol mainly undergoes direct deoxygenation,hydrocracking,and Alkylation reaction.The pore structure of the catalyst directly affects its catalytic performance and product selectivity.La₂FeNiO₆ double perovskite oxide samples with average pore diameters of 18.1nm,15.1nm and 12.5nm were prepared using polystyrene colloidal crystal templates of different sizes.The sample with an average pore diameter of18.1nm has a higher catalytic activity at a reaction temperature of 400°C,the conversion of m-cresol reaches 35.7%,and the selectivity to toluene is 82.1%.At the same time,the catalyst has a lower surface carbon content during the initial activity test.,The larger pore size is conducive to the diffusion of the carbon precursor on the catalyst surface area and inhibits the surface carbon of the catalyst.