Controllable Construction Of Au/Amyloid Peptide Nanocomposites Based On Peptide Self-assembly And Its Catalytic Reduction Performance

The development and preparation of highly efficient catalysts can effectively solve the problems of energy shortage and environmental pollution.Supported precious metal catalysts are the current research hotspot.Noble metals have the advantages of low temperature,high catalytic activity and high recyclability,but the active components are prone to aggregation,and the existence of supports can improve the distribution of precious metal nanoparticles and increase the stability of the catalyst.However,the synthesis conditions of traditional catalyst support materials are complex,which easily cause environmental problems and high energy consumption,and the catalytic activity is not ideal.In response to the above problems,this article mainly carried out a new type of nano-catalyst using amyloid peptide as a biological template to regulate the synthesis of noble metal biological template and its application in catalytic hydrogenation reaction.In this work,we first study the effect of glow discharge treatment on the self-assembled structure of human islet amyloid peptide(hIAPP)20-29(SNNFGAILSS);then prepare two Au/hIAPP20-29 nanocomposites with different structures by the glow discharge method and the sodium borohydride reduction method;and applied materials to the catalytic hydrogenation of p-nitrophenol.It provides a certain guiding significance and theoretical basis for the synthesis of noble metal catalysts by the peptide template method.The specific research content and results are as follows:1.hIAPP20-29 can be assembled from a monomer state into a mature fiber structure after 6 hours of incubation in an aqueous solution,and the secondary structure changes from the original random structure to the?-sheet structure.After glow discharge treatment,the self-assembly morphology and secondary structure of hIAPP20-29 were significantly different.After incubated for 120 h,peptides finally self-assembled into a uniform two-dimensional thin film structure with a height of2.78±0.19 nm and its secondary structure is random structure.The results show that the glow discharge treatment can effectively control the self-assembly structure of hIAPP20-29,which lays the foundation for the subsequent construction of functional materials.2.The mixed solution of hIAPP20-29 and chloroauric acid was treated by glow discharge,and the Au/hIAPP20-29 membrane composite was successfully synthesized in one step.The Au nanoparticles reduced by glow discharge are uniformly attached to the polypeptide film structure.The size of the Au particles is controllable,which is mainly determined by the initial solubility of chloroauric acid.The lower the solubility of the initial chloroauric acid,the smaller the size of the synthesized Au nanoparticles.Then we use hIAPP20-29 fibers directly incubated as a template.The Au/hIAPP20-29 fiber nanocomposite was successfully prepared by the sodium borohydride reduction method.3.The Au/hIAPP20-29 membrane and Au/hIAPP20-29 fiber are used to catalyze the reaction of p-nitrophenol.When they were placed at room temperature for 24hours,the activity of the catalyst for synthesis of peptide template is much higher than the template-free catalyst.Under the conditions of 20?and substrate concentration of 75?M,the TOF of Au/hIAPP20-29 membrane and Au/hIAPP20-29 fiber can reach95.13 h^-1 and 74.71 h^-1;the reaction rate constant is 0.2172 min^-1 and 0.1797 min^-1.The reaction kinetic equation was established,and the activation energies of Au/hIAPP20-29 membrane and Au/hIAPP20-29 fiber were 26.09 k J·mol^-1 and 24.82k J·mol^-1,respectively,and the reaction order was 0.44 and 0.66,respectively.The result shows that hIAPP20-29 is an effective template for the construction of high-activity catalysts.Both Au/hIAPP20-29 catalysts with different structures show high catalytic performance.The two-dimensional membrane structure catalyst shows a higher catalytic conversion frequency and lower reaction energy level than the one-dimensional fiber structure.It can be seen that the two-dimensional peptide membrane structure has more advantages than the one-dimensional peptide fiber structure in catalysis.