Synthesis And Application Of Nanomaterials Based On Amino Acids

In this paper,the synthesis and application of two new nanomaterials?nanoclusters,NCs?and carbon dots?carbon dots,CDs?are introduced.The shortcomings of Cu NCs with poor stability and low quantum yield of carbon quantum dots are mainly studied.The contents of the study are as follows:?1?An ultra-stabilized Cu NCs was successfully synthesized by using proline as a protective agent and hydroxylamine hydrochloride?NH₂OH·HCl?as a mild reducing agent.The characterization of TEM shows that the prepared Cu NCs has good dispersibility and no large aggregates or copper nanoparticles,with an average size of about 1.88 nm.The XPS characterization of Cu NCs showed that the Cu²⁺was reduced to Cu,but the existence of a small amount of Cu⁺could not be ruled out.The synthesized Cu NCs showed good stability in the range of physiological related pH,five months of storage time,high ionic strength solution,high concentration H₂O₂ and various common metal ions.The synthesized Cu NCs is sensitive to pH and can be used in pH sensor.For the first time,the effects of various organic solvents on the fluorescence properties of Cu NCs are studied.?2?For the first time,Fe²⁺was doped in an aqueous solution containing proline as a carbon source.Fe²⁺-doped CDs were successfully synthesized by heating in a water bath at80°C.TEM showed that the Fe²⁺-doped CDs were spherical in shape and uniform dispersions without apparent aggregation.The average particle diameter was 1.93±0.3nm.In addition,we combined the cysteine?Cys?functional Fe²⁺-doped CDs with Au NCs to form a sensitive nanohybrid.By adjusting the volume ratio of the blue fluorescent CDs and the red fluorescent Au NCs,color-tunable nanohybrid can be obtained.In the presence of Zn²⁺,the fluorescence intensity of Au NCs was enhanced,which resulted in the fluorescence of nanohybrid changing to pink.In the presence of Ni²⁺,nanohybrid turned to blue because the red fluorescence of the Au NCs was quenched.Upon addition of histidine?His?,the pink PL was gradually recovered based on the high affinity of His with Ni²⁺.In a word,the blue-pink and pink-blue-pink detection of Zn²⁺and His by the two distinct fluorescence color change were developed successfully.?3?Fe³⁺-doped CDs with tryptophan as protective agent was synthesized quickly and conveniently by microwave irradiation.TEM characterization showed that the Fe³⁺-doped CDs had good dispersibility and the average size was about 6.3 nm.XPS shows that Fe³⁺has been successfully incorporated into the prepared CDs,and the valence state of Fe³⁺has not changed any more.The IR spectrum further shows that Fe³⁺may be in the form of Fe³⁺doped CDs in the form of coordination.We found that the fluorescence intensity of Fe³⁺-doped CDs has excellent recoverability between pH 3¹0.The CDs has a special solvent effect in the ethylenediamine solution,and the fluorescence color shows a different yellow green property from the blue color of the aqueous solution.