Research On Preparation Of Mimetic Enzyme Based On ZIF-8 And Their Biomimetic Catalytic Performance

Biomimetic catalytic oxidation technology is a catalytic technology to achieve catalyst air oxidation in the mild conditions.Biomimetic catalysis not only has the characteristics of enzyme catalytic reaction-high efficient catalytic activity,high degree of transfer reaction,but also has the advantages of chemical catalysis-good catalytic stability,high selectivity.Biomimetic catalysis of metal porphyrin is an important research direction of porphyrin chemistry.The study of highly active porphyrin-carrier biomimic enzyme shows a broad application prospect.ZIF-8 is a stable,green catalyst carrier.In this paper,therefore,ZIF-8 was selected as the supporter to prepare hemin/ZIF-8,and its catalytic activity and microenvironmental impact mechanism were studied.Firstly,a hemin/ZIF-8 composite has been prepared for the first time by one-pot via chemical bond interactions.TEM?EDS?FT-IR analysis suggested that hemin/ZIF-8 was successfully prepared.It showed a good peroxidase-like activity in acidic environment.It had great affinity to TMB and showed a good linear relationship within 5-50 mM glucose concentration(R~2=0.9991).There was no significant decrease in the catalytic activity after six recyclesSecondly,hemin/Ca-alginate/ZIF-8 composite with a diameter of 1.5 mm has been prepared by layer-by-layer method.SEM,XRD,FT-IR analysis suggested that it was made up of hemin/Ca-alginate nucleus and ZIF-8 shell.The dissolved problem of microspheres was solved by replaciing aqueous solution with calcium chloride solution of 2-methyl imidazole and utilizing the ion exchange properties of sodium alginate.The composite showed the good catalytic activity,and the catalytic activity was effected by different pH,temperature and substrate concentration.Finally,the mechanism of environment impact was investigated.Uv analysis and EDTA experiments showed that 2-methylimidazole as an organic ligand of ZIF-8 can combine with the Fe in the hemin,which promotes the electron transfer and increases the catalytic reaction rate.