Ming Ruan,Huajing Zhou,Lingxiang Zhao,Tianding Hu,Liang He,Shaoyun Shan
It is feasible to improve the photodegradation efficiency of organic pollutants by metal-organic frameworks (MOF)-based semiconductors via ligand engineering. In this work, three (Fe/Co)-XBDC-based MOFs were synthesized by introducing different ortho-functional groups X (X = –H, –NO 2 , –NH 2 ) next to the carboxyl group of the organic ligand (i.e., terephthalic acid). The analysis focused on the influence mechanism of the adjacent functional group effect of the ligand on the physicochemical properties of the material and the actual photodegradation activity of TC . Multiple pieces of evidences suggested that the differences in electron-induced and photocharge-transfer mechanisms of the above ortho functional groups affect the crystal morphology and photocatalytic activity of FeCo-MOF during pyrolysis . Interestingly, (Fe/Co)–NH 2 BDC exhibited the highest photocatalytic activity under neutral conditions. The results of density functional theory show that the introduction of a strong donor-NH 2 group can enhance light absorption and act as an “electron pump” to supply electrons to the iron center, accelerating the separation and efficient transport of photogenerated carriers on the ligand-metal bridge. In conclusion, this study is a proposal for a strategy of structural regulation for the enhancement of the catalytic activity of (Fe/Co)-MOFs in the photodegradation of TC.
Tao Lu,Tengfei Yu,Yaqi Yan,Huan Li,Zhiguang Suo,Qian Li,Min Wei,Huali Jin
Aflatoxin B1 is one of the most toxic carcinogens and has been classified as a group I carcinogen by the International Agency for Research on Cancer. AFB1 is widely distributed in the natural environment and may be present in various grains and products. Therefore, it is significant to establish a strategy for in site detection of AFB1 accurately. Herein, a portable electrochemical aptasensor was developed for accurate detection of AFB1. A screen-printed electrode was selected as the working electrode, which improves the portability and practical application of the aptasensor. The use of gold-nanoparticles/FeCo-MOFs as electrode modification materials improves both the electron transfer efficiency and the large number of connected signal probes. Daisy-like bimetallic PtPd nanoflowers have rich specific surface area, providing numerous sites for loading of the signal molecule thionine. Additionally, the catalytic hairpin assembly cycle amplification strategy was implemented to effectively enhance the sensitivity of the aptasensor. Under optimal conditions, the sensor exhibited a detection range of 0.001–500 ng/mL and a limit of detection of 0.818 pg/mL. The developed aptasensor exhibited positive analytical performance in real samples, quality control samples and toxin samples produced by aspergillus flavus. This work advances the development of portable, sensitive and in site analytical methods, with promising applications in food safety field testing.
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