Sythesis,Characterization Of Low Dimensional Transition Matel Oxide And Their Application In Catalysis And Analytical Detection

With the development of nanoscience and nanotechnology,nanomaterials are increasingly approaching human life.Compared with the expensive noble metals,transition metal nanomaterials have the characteristics of high reserves on the earth,low cost,and good photoelectric effect.So they are extensively researched in the fields of energy catalysis,environmental monitoring,sewage treatment and biomedicine.With high surface energy,zero-dimensional nanomaterials is easy to agglomerate.So zero-dimensional nanomaterials may reduce catalytic activity and cycle-ability in the process of reuse.Therefore,preparing the one-dimensional nanomaterials of high stability through the simple method?electrospinning technology?has much more practical application value.Similarly,2D nanosheet self-assembled one-dimensional nanotube layered structure has attracted great attention in many fields.This is due to its special physical and chemical properties and potential application value.Two-dimensional nanomaterials have been extensively studied in probe sensing and catalysis because of their high atomic exposure ratio and electron conductivity.However,two-dimensional materials also have some drawbacks such as poor stability.Therefore,combining a high-stable 1D material with a high catalytically active 2D material can not only ensure the high activity of the catalyst,but also improve the cycle stability of the nanomaterial in practical applications.In this paper,we mainly use a low-cost transition metal as raw material to prepare a series of low-dimensional transition metal oxides.We not only prepared the metal oxides by electrospinning and ultrasound,but also studied their application in biological detection and clinical application prospects.The details are summarized as follows:?1?We first report the design and synthesis of highly efficient folic acid-conjugated hydrogen-generation tube-in-tube CuO/Co₃O₄ heterojunction nanofibers for highly sensitive and rapidly recognition of cancer cells through pressure signal under visible light irradiation.The resultant nanofibers can dramatically enhance the hydrogen-generation activity of ammonia borane under visible light irradiation.Such hydrogen-generation reaction can translate a molecular recognition event between folic acid and folate receptor to measurable pressure signal readout through a low-cost and portable pressure meter for target cancer cell detection.Limit of detections?LODs?down to 50 cells mL^-1 in only 15 mins can be achieved.This result is superior to those of the other reported methods,indicating the superiority of the new pressure-based sensor in terms of sensitivity.The present study establishes the pressure meter as a useful tool for early clinical point-of-care cancer diagnosis.?2?Here,a green approach is proposed for synthesis of MnCo₂O₄ nanotubes.The resulting nanotubes have been shown to have peroxidase activity that catalyzes the oxidation of 3,3',5,5'-tertamethylbenzidine?TMB?by O₂,resulting in a typical color reaction from colorless to blue.Moreover,such nanotubes exhibit excellent catalytic properties for the decomposition of H₂O₂ into O₂,resulting in a significant increase in pressure in the bottle.Thus,a new sensor system using MnCo₂O₄nanotubes as an artificial peroxidase,generating O₂ as pressure signal,and TMB as a color change reporter molecule for dual-mode pressure-based?pressuremeter?and colorimetric?naked eye?detection of cancer cells was established.By using folic acid?FA?as a recognition element,a total of 50 folate receptor?FR?positive cancerous cells can be distinguished by naked-eye observation and pressure meter.The clinical applicability of such dual-mode strategy has been tested in detecting cancer cells in serum samples.We envisaged that such dual-signal readout dual-mode strategy based on MnCo₂O₄ nanotubes offers a promising biosensing platform for early clinical diagnosis.?3?Herein,a simple and versatile approach was developed to synthesize hierarchical nanosheets constructed MCo₂O₄?M=Ni,Cu,Zn?hollow nanotubes.Core-shell polyacrylonitrile?PAN?/M-cobalt ultrathin nanosheet composite nanofibers are first synthesized by the reaction between PAN/M-cobalt acetate hydroxide precursors and NaBH₄.After calcinating treatment,theses nanofibers as precursor could be easily transformed into the corresponding hierarchical nanosheets constructed MCo₂O₄ hollow nanotubes.By applying a phothcatalyst,the resultant MCo₂O₄ nanotubes,especially the CuCo₂O₄ nanotubes,exhibit highly photocatalytic activity and cycle stability toward water oxidation reaction with O₂ generation rates of51.1mmolg^-1h^-1 under visible light irradiation,which is higher than most reported catalysts.This approach is very versatile and can be applied to synthesize other hierarchical multi-element oxides nanosheets constructed hollow nanotubes for advanced applications.?4?In this work,a serious of multielement transition metal oxides high-entropy ultrathin nanosheets with a uniform morphology and a thickness of about 2 nm were successfully prepared.In order to verify the superiority of high-entropy nanosheets,we tested its catalytic detection of glucose.These nanosheets,especially the?Cu,Zn,Mn,Ni,Fe?-Co-O nanosheets,show high sensitivity detection of glucose with a minimum detection line of 0.6?M,which is significantly better than the reported catalyst.