Preparation Of MXene-containing Composite And Exploration Of Their Catalytic Performance

Two-dimensional layered transition metal carbide/nitride(MXene)has a wide range of applications in adsorption,catalysis,energy storage,sensors and other fields,due to its tunable interlayer space and surface functional groups,as well as unique electrical,optical and thermodynamic properties.In this paper,the composite materials with semiconductor and metal,and their catalytic performances were systematically studied.The main research contents are as follows:(1)Three kinds of Ti₃C₂-Zn O composite materials with different morphologies were prepared by co-precipitation method,reflux method and hydrothermal method,and the performance of photocatalytic reduction of Cr(?)was investigated.The study found that the Ti₃C₂-Zn O composite materials obtained by co-precipitation and reflux method could improve the photocatalytic reduction of Cr(?)activity.Furthermore,a photocatalytic oxidation-reduction system was constructed,that is antibiotics or environmental hormones were added during the photocatalytic reactions.It was found that the Ti₃C₂-Zn O composite material prepared by reflux method and hydrothermal method could promote the photocatalytic reduction of Cr(?).Furthermore,a series of characterization of the catalyst were carried out,and the possible photocatalytic reduction mechanism of Ti₃C₂-Zn O composite material was discussed.(2)Au/MXene and Cu/MXene catalysts were prepared by impregnation-reduction method,and used for catalytic reduction of nitroaromatics at room temperature.It was found that the size distribution of Au in the Au/Ti₃C₂ catalyst is 10-100 nm and that in Au/Ti₂C catalyst is 5-50 nm,respectively.It shows that for the supported Au catalyst,different supports have a great influence on the regulation of metal particle size and catalytic activity.On the contrary the Cu/MXene catalysts obtained by different methods and different supports have the same Cu size distribution,with the range of 4-10 nm,and exhibit excellent catalytic activity in reducing nitroaromatics.It was indicated that the preparation method and support have little influence on the size control and catalytic activity of supported Cu catalyst.Furthermore,the possible catalytic reaction mechanism for the reduction of nitroaromatics with supported metal catalysts is proposed.(3)Ti₃C₂-Cd S composite was prepared by in-situ growth of Cd S nanoparticles on Ti₃C₂ by two different methods,and the photocatalytic reduction of Cr(?)and reduction of nitro aromatics were studied.Then found that introduction of Ti₃C₂ could improve photogenerated carrier transfer rate,thereby improving the photocatalytic efficiency and the stability of catalyst.Through the comparison of two preparation methods,it was found that the photocatalytic activity of Ti₃C₂-Cd S composites prepared by the reflux method is better than that of the co-precipitation method.Additionally,the possible photocatalytic reaction mechanism was discussed.