Bio-Based Controllable In-Situ Growth Of Submicro/Nano Materials And Their Properties

In recent years, with the dynamic development of biological technology and the increasing pervasion and interaction between biology and materials chemistry, controllable synthesis of micro/nano materials with given structure, dimension, shape and size by using biomolecule as template has become the hot topic of study. In this paper, we, for the first time, chose the most common biomolecules in laboratory, T4 phage and Escherichia coli (E.coli), as the templates to control the in-situ growth and assembly of monodisperse metal and alloy nanoparticles and the synthesis of uniform ZnS submicrorods. The structures, morphologies and properties of samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), photoluminescence (PL), cyclic voltammograms (CV) and superconducting quantum interferece device (SQUID) magnetic property measurement system and so on. The details and results are summarized as follows:Based on the assistance of T4 phage, the in-situ growth and assembly of noble metal particles, Pt, Rh and Pd, on T4 capsid were realized. The organized noble metal particles have a small size and size distribution (3~5.5 nm), and are patterned dispersedly on the out surface of T4 capsid. The coverage density of noble metal particles on T4 capsid were controlled simply by adjusting the concentration of metal salt solution, incubation time and cycles. The preparation of noble metal@T4 shell-core structures with uniform size could also be achieved. Cyclic voltammogram tests reveal that the amount of hydrogen adsorption of organized noble metal nanoparticles is 5~10 times higher than that of the noble metal solids prepared without using template, indicating a great improvement in electrocatalytic activity. Based on these experimental results and complex theory, a possible mechanism for the formation of noble metal nanoparticles and nanoshells on T4 capsid was discussed.With assistance of T4 phage, the in-situ growth and assembly of magnetic metal particles, Fe, Co and Ni, on T4 capsid were realized. Also, the magnetic metal@T4 shell-core structures were successfully synthesized. The organized magnetic metal quantum particles as small as 2~4.5 nm are patterned over the whole viral capsid surface with a high degree of monodispersity. The influences of pH, concentration of metal salt solution, incubation time and cycles on the growth and assembly of magnetic metal particles on T4 capsid were investigated. Quantum design magnetic properties measurements reveal that the organized Fe and Co quantum particles present observable ferromagnetic behavior. Based on these experimental results and electrostatic adsorption theory, a possible mechanism for the formation of magnetic metal nanoparticles and nanoshells on T4 capsid was discussed.With assistance of T4 phage, the in-situ growth and assembly of four alloys, Pt-Pd, Pt-Rh, Pt-Fe and Pt-Co, on T4 capsid were realized. The as-synthesized Pt-Pd and Pt-Rh are alloy nanoparticles with size varing between 3 and 8 nm, and Pt-Fe and Pt-Co are alloy metal shells coating on T4 capsid with thickness of about 5~10 nm. Cyclic voltammetry tests reveal that the amount of hydrogen adsorption of Pt-Pd/T4, Pt-Rh/T4 and Pt-Co/T4 catalysts is 3~7 times higher than that of Pt solid prepared without using any template. The magnetic results reveal that samples of Pt-Fe/T4 shell-core structure is superparamagnetic and Pt-Fe/T4 still exhibit observable ferromagnetic behavior with coercivity of 44.6 Oe.Based on the assistance of E.coli, the controllable nucleation and growth of ZnS particles in E.coli cell were realized. The as-synthesized ZnS submicro particles are uniform in size and have a short-rod structure becaused of the steric confinement effect of E.coli. Photoluminescence investigation reveals that ZnS particles present a small surface flaw and a special fluorescence property which is different from that of the bulk and nanometer ZnS materials.