The Application Of Iron-doped Molybdenum Carbide In The Hydrogenation Of Aromatics

Catalysis chemistry plays an indispensable role in industrial production and the economic development.In 2017,the total output value of the world’s production of catalysts has reached 3 billion dollars.Moreover,the industrial production using various catalysts is hundreds of billions dollars.With the rapid development of Chinese industry,people’s requirements for environmental protection are constantly improving.To develop high efficiency,low toxicity and low cost catalysts to replace high toxicity catalysts or noble metal catalysts is one of the urgent problems.In this work,molybdenum carbide with iron as auxiliary agent was prepared,and toluene hydrogenation reaction was used as the probe experiment.By exploring the optimal preparation conditions,the catalyst with the best hydrogenation performance was selected and the interaction between iron and molybdenum carbide was explored.The precursor was prepared by solid-solid mixing method,and the iron-doped molybdenum carbide catalyst was prepared by temperature programmed reaction.We explored the effect of the degree of carbonization and the doping amount of iron on the physicochemical properties of molybdenum carbide.A series of iron-doped molybdenum carbide catalysts were prepared by adjusting the carbonization temperature to control the degree of carbonization and adjusting the doping amount of iron.The physicochemical properties of the catalyst samples under different preparation conditions were investigated by BET,ICP,XRD,XPS,LRS,MES,SEM,TEM and other characterization methods.The catalyst was evaluated for toluene hydrogenation performance on the fixed bed reactor.The reaction conditions were:100℃,3.0 MPa,toluene:hydrogen=1:100,0.3 h-1.The evaluation results show that the iron doping amount is 1.5 mol%,and the molybdenum carbide with a carbonization temperature of 550℃ has the best hydrogenation reaction performance.The correlation between catalytic activity and its structure was discussed preliminarily,and the reasons for catalyst deactivation were explored.The catalyst with the best hydrogenation performance(1.5Fe-Mo2C-550)is supported on different supports such as oxide,molecular sieve and carbon.A series of supported molybdenum carbide catalysts were prepared with a loading of 20 wt%.The supported catalyst was characterized and the hydrogenation activity of toluene was studied to find the supported catalyst with the best hydrogenation performance,which was 1.5Fe-Mo2C-Al2O3.The catalyst has a larger specific surface area and better catalytic activity than the unsupported catalyst.Finally,the electrochemical activity of doped molybdenum carbide was also studied in this work.We prepared a series of copper doped molybdenum carbide and carried out hydrogen evolution reaction.It can be found from the test results that doped molybdenum carbide can significantly improve its electrochemical reactivity.The catalyst with the best performance is lOCu-MoC,whose electrochemical performance is close to commercial Pt/C catalyst.This provides new evidence for expanding the use of molybdenum carbide.