Catalytic Properties And Application Of Manganese Oxide Nanowase

Nanoenzymes refer to a class of functional nanomaterials with enzymatic properties such as catalytic efficiency and enzymatic reaction dynamic properties similar to natural enzymes.Compared with natural enzymes,nanoenzymes have high stability,low cost,easy preparation,and good The advantages of biocompatibility have received extensive attention in many fields such as biosensing,environmental treatment,disease diagnosis and treatment.More importantly,the unique physicochemical properties of nanozymes not only make them have adjustable catalytic activity,but also provide more possibilities for expanding their analytical sensing applications.Manganese-based nanomaterials have the advantages of easily adjustable and controllable catalytic activity,strong stability,etc.,and have become an emerging research hotspot in the field of nanoenzymes.In this study,manganese-based nanomaterials were prepared by hydrothermal reaction and calcination methods,starting from the design and regulation of the catalytic activity of nanoenzymes,and further combining with colorimetric detection technology with advantages of on-site diagnosis and naked eye recognition to explore its practical application Prospects and achieved some useful results.The specific research content of this paper is as follows:1.MnO₂-Fenton“on-off”colorimetric probe to detect H₂O₂and glutathione.Using simple solution mixing method and ultrasonic stripping method to prepare single-layer MnO₂nanosheets,through ultraviolet visible spectroscopy(UV-vis),transmission electron microscope(TEM),scanning electron microscopy(SEM),X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),Fourier infrared spectroscopy(FTIR)and other characterization techniques explored its morphology,structure,element composition and optical properties.Because MnO₂nanosheets have peroxidase-like activity,they can catalyze the oxidation of3,3',5,5'-tetramethylbenzidine(TMB)to blue ox-TMB by hydrogen peroxide(H₂O₂),With the aid of the Fenton reaction,it can catalyze H₂O₂to produce more hydroxyl radicals(·OH),thereby improving the catalytic activity of MnO₂nanosheet peroxidase and accelerating the color reaction.At the same time,glutathione(GSH)can effectively inhibit the oxidation of the enzyme substrate TMB to produce blue,and the change in the absorbance of oxidized TMB at 653 nm has a good linear relationship with the concentration of GSH within a certain range.Based on this,a colorimetric sensor system for rapid and sensitive detection of H₂O₂and GSH was successfully constructed.Under optimized conditions,the linear range of this method for measuring H₂O₂is:50-350?M,and the detection limit is 0.15?M;The linear range of GSH is 0-13.5?M,and the detection limit is 0.04?M.This method has been used for the detection of GSH in human blood samples with satisfactory results.2.Photocatalytic degradation of o-chlorophenol by Mn₃O₄-Fenton nanoenzyme.This paper uses a simple hydrothermal method to synthesize Mn₃O₄nanoparticles,and uses SEM,XRD,XPS and other characterization methods to explore their size,particle crystal form,surface chemistry and other properties.Mn₃O₄NPs not only show good oxidase-like activity for TMB,OPD,ABTS and other enzyme substrate reactions,but also Mn₃O₄NPs also have peroxidase activity.In addition,the Mn₃O₄-Fenton system exhibits a good photocatalytic degradation ability for o-chlorophenol(o-cp).·OH and·O₂^-play an important role in the photocatalytic degradation of o-cp.Combined with LC-MS,a possible photodegradation pathway of o-cp is proposed based on the identified intermediate products.The factors affecting catalytic degradation(including:preparation conditions of the catalyst,light time,p H of the solution,the amount of catalyst added,the initial concentration of the solution,etc.)are optimized for a single condition.The mineralization of o-cp proves the strong oxidizing ability of the Mn₃O₄-Fenton system,which can decompose pollutants into carbon dioxide and water.Under optimal conditions,the degradation rate of o-cp can reach 87%.3.Selective detection of TBHQ based on Mn₃O₄/AuNPs composite oxidase.In this paper,iodine and copper doped carbon dots are used as reducing agents,polypropylene imine is used as protective agent,and gold nanoparticles(AuNPs)are obtained by reducing chloroauric acid.Through the surface regulation of Mn₃O₄NPs by AuNPs,we propose a Mn₃O₄/AuNPs complex enzyme,realizes the enhancement of nanozyme oxidase activity under neutral p H conditions.With tert-butyl hydroquinone(TBHQ)as the substrate,the oxidized TBHQ is a red oxidized quinone(TQ).Based on the characteristic that the concentration of TBHQ and the measured TQ absorption peak show a good linear relationship,the establishment of high sensitivity,a new method for the detection of TBHQ with strong selectivity and good reproducibility,with a detection limit of 0.1 mg/kg.The biggest advantage of this research system is strong specificity,and it has little effect on the interfering substances that may be produced and coexist in practical applications,such as synthetic phenolic antioxidants,amino acids,and sugars.Based on the above description,this research has good prospects for the determination of TBHQ in flavors and fragrances.