Preparation And Acetone Fluorescence Sensing Properties Of Eu-MOFs Based Materials

Acetone is a dangerous chemical,easy to cause toxicity and explosion,but also easy to make drugs and explosive.In addition,diabetes mellitus can be diagnosed noninvasive by the concentration of acetone in the breath of organisms,and the health status of animals can be judged and the degree of vegetable preservation can be measured.Therefore,acetone concentration detection is of great significance in social security,industry,medical treatment,food and so on.Sensor detection method stands out among many acetone concentration detection methods because of its small,cheap and easy on-line detection.One of the core components of the sensor is sensing materials.Among them,Ln-MOFs materials have better sensitivity,higher selectivity and can work at room temperature,so they became a hot research topic in this field rapidly.The Ln-MOFs materials for acetone detection are mainly divided into En-MOFs and Tb-MOFs materials,and the sensitivity of the former is obviously better than that of the latter.Although En-MOFs materials have many advantages in the detection of acetone,there are still some hard problems to be solved.For example,the occupational exposure limit for acetone set by the American Conference of Governmental Industrial Hygienists is 750 ppm,but there are still few materials that meet the environmental testing application.Furthermore,the minimum detection limit of acetone concentration in En-MOFs materials is only 30 ppm,which faces great challenges in low concentration detection,such as noninvasive diagnosis of diabetes mellitus(healthy people < 0.9 ppm,diabetic patients > 1.8 ppm).Moreover,the role of electron transfer in the fluorescence sensing mechanism of acetone is not clear.At the same time,there are relatively few data on the morphology,specific surface area and pore size distribution of En-MOFs materials in fluorescence sensing research.Finally,there is a lack of reports on the types of adsorption between them.Therefore,three kinds of europium based metal organic skeletons,Eu-BPDA,EuBDC and Eu-BTC,were prepared by solvothermal synthesis.The crystal structure,morphology,specific surface area,pore size distribution,sensing performance,sensing mechanism and adsorption type of the three materials were studied.The results show that the sensitivity of dispersed micrometer crystals Eu-BDC(0.065 vol%)and dispersed thinlayer-bunch crystals Eu-BTC(0.060 vol%)composed of a large number of nanoparticles to acetone is lower than the occupational contact limit of acetone.(0.075 vol%),It is expected to be used to monitor the concentration of acetone in the environment.The sensitivity of Eu-BPDA material(0.105 vol%)to acetone was higher than that of most Ln-MOFs(0.105 vol%-10 vol%),but it was lower than that of Eu-BPDA material(0.028 vol%)due to the large partical size and poor structure stability for synthesis parameters.In addition,in terms of fluorescence sensing mechanism,electron transition plays a negative role in fluorescence quenching.Next,it is expected to be used in the application of lower detection limit of acetone in order to further improve the sensitivity of Eu-BDC to acetone.On the one hand,the sensitivity of Eu-BDC to acetone was increased by 30.8%(0.065 vol%-> 0.045 vol%)by reducing the size of crystal particles for increasing the specific surface area with inverse microemulsion and shortening the synthesis time.On the other hand,based on the fluorescence sensing mechanism,the sensitivity of acetone and materials was further increased by 55.6%(0.045 vol%-> 0.020 vol%)by adjusting the competitive absorption ability of acetone and materials to excited light energy.Its performance exceeds that of Eu-BPDA material,but it is still a certain distance from the low acetone detection limit of noninvasive diagnosis of diabetes mellitus.Finally,it is expected that the method in this paper can provide some references for the preparation and application of Ln-MOFs materials with lower acetone detection limit.In addition,the sensitivity order of the materials to acetone is the same as that of the powder fluorescence intensity of the materials,which is expected to improve the research efficiency.