A Composite Fe-V/g-C₃N₄ For Catalyzing Liquid-phase Selective Oxidation Of Methanol

In this paper,a composite material Fe-V/g-C₃N₄ was prepared by impregnation method.The prepared materials were characterized by XRD,FT-IR,SEM,TEM,XPS and N₂ adsorption-desorption technique.The results showed that the prepared composite material was composed of V₂O₅,FeVO₄ and g-C₃N₄ crystalline with higher specific areas.The catalytic performance of the prepared composite material Fe-V/g-C₃N₄ for liquid-phase oxidation of methanol was evaluated by using O₂ as oxidant.The relationship between excellent catalytic performance and surface structure and composition was obtained.It was clear that the active sites on the catalyst surface are V₂O₅ and FeVO₄ crystals.The effects of catalyst preparation conditions and reaction technology conditions such as oxygen pressure,reaction time,reaction temperature,and catalyst amount on the reaction were investigated.The optimum calcination temperature of the catalyst was determined to be 550°C and the optimal reaction conditions were:reaction temperature of 175°C,the reaction time 6 h,the oxygen initial pressure 1MPa,and the amount of catalyst 0.2 g.Under the optimum conditions,the conversion of methanol was 34.3%and the selectivity was more than 93.0%.A pioneered strategy for tuneable synthesis of DMM and POM was realized by controlling the reaction time.In addition,the catalyst was separated by filtration after the reaction,dried,and then reused in the next run.The catalytic activity of the catalyst was not significantly affected when used for the third time in a batch reaction.Besides,the catalyst lifetime test in a fixed-bed reaction showed that the catalytic activity of the Fe-V/g-C₃N₄ catalyst maintained until continuous reaction time of 26 h,indicating that Fe-V/g-C₃N₄ catalyst has excellent reusability and stability.