Study On Titanium-based Mxene's Physical And Chemical Properties And Their Applications

As a new kind of two-dimensional materials,MXene have a wide variety and are enriched with large number of functional groups on the surface,which makes it exhibit different properties with traditional two-dimensional materials,and have attracted extensive attention from researchers.Although MXene have been deeply researched and developed by virtue of their unique electronic properties and excellent optical,magnetic,mechanical properties,and have been applied in different fields such as energy storage,catalysis,biological sensing,electromagnetic shielding,compared to traditional two-dimensional material,there are still some properties worthy of further mining and utilization.Similar to other two-dimensional materials such as graphene or Mo S₂,MXene has photoluminescence properties,but the existing reports mainly focus on the down-conversion fluorescence,which limit the application of MXene in bioanalysis;MXene are reductive because of the high density of surface defects on the surface,however,there are few reports on in-depth development of this nature.Based on these,we have thoroughly studied the most common titanium-based MXene on its photoluminescence properties and its reducibility due to surface defects,providing new ideas and basis for broadening the application prospects of MXene materials.The main research contents and conclusions are as follows:1.Ti₃C₂ nanosheets are successfully synthesized,and the corresponding fluorescence behaviors of Ti₃C₂ nanosheets were deeply investigated.In addition to the down-conversion emission,more surprising,the excellent up-conversion emission behaviors are also found and the corresponding reasonable emission scheme was successfully elucidated.Ti₃C₂ nanosheets exhibited an up-conversion fuorescence with a narrower full width at half maximum(FWHM)of 17 nm and a longer fluorescence lifetime about 1.18?s,covering almost all of visible light at the different excitation wavelength of near infrared light.Furtherly,based on the quenching effect of L-tryptophan on up-conversion fluorescence intensity,a fast,simple and label-free L-tryptophan fluorescence sensor with excellent selectivity was achieved,showing a limit of detection(LOD)as low as 91 nM.Current research suggest may open new opportunities for the design of novel up-conversion fluorescence probe to boost its potential applications in bio-sensing and imaging.2.The high-density defects on the surface of MXene make it reducible.Based on this property,composite material of Prussian blue and MXene(PB/Ti₃C₂)is in-situ synthesize and used as a catalyst for oxygen evolution reaction(OER)in alkaline medium.Its catalytic performance is much better than single material or similar composite material synthesized by physical adsorption with a potential of 1.63 V at 10mA cm^-2.PB and Ti₃C₂ are combined through strong interaction,the structure is more stable,and the electrochemical test shows good electrochemical stability.The experimental results provide a more convenient design idea for the in-situ growth of MXene-based materials,and explore the potential applications of MXene-based materials in the field of catalysis.