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On Synthesis and Properties of Oxides with Biogenic Hierarchy Using Plant Leaves as Templates and Biogenic Nitrogen-doped Ceria Using Biomass as Nitrogen Source-Toward Superior Materials and Greener Chemistry

Author: ZhouShuJun
Tutor: FanTongXiang
School: Shanghai Jiaotong University
Course: Materials Science
Keywords: Genetic state preparation Hierarchy Biological structures Biological Nitrogen Plant leaves Biomass Oxygen storage Fluorescence
CLC: O614.332
Type: Master's thesis
Year: 2009
Downloads: 162
Quote: 2
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Abstract

After hundreds of millions of years of evolution, nature produces a variety of complex structures that are linked with different biological functions. Bionic is a modern development of new materials is an important means by which the genetic state preparation is a branch of bionic. Genetic state preparation using natural biological material obtained as a template structure with biological material left state. Material properties and structure, as genetic material combines the natural biological state of the structure and function of artificial ingredients, easy to get new or improved performance. In addition to genetic patterns, leaving state preparation also involves genetic component, refers to the genetic material inherited biological state of the template elements. In this study, two attempts were made. On the one hand, to plant leaves as a template with a hierarchical structure prepared by the legacy of state oxides, including camphor leaves and oleander leaves as a template to prepare ceria and red maple leaves as a template Eu-doped calcium silicate. On the other hand, biomass as nitrogen oxides of nitrogen-doped, including rice and soybeans as nitrogen nitrogen-doped ceria. For microstructure of these materials, components, nano-pore structure, oxygen activity, fluorescence, absorption characteristics were characterized, including X-ray diffraction, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, nitrogen adsorption isotherm, TPR, raman spectroscopy, UV - visible absorption and fluorescence spectra. The main conclusions obtained are as follows: 1. Oleander leaves with camphor leaves and left state as a template prepared ceria. Genetic state hierarchical pore structure having ceria. At the micron scale, inherited the leaf template morphology and pore structure; at the nanoscale, with a narrow pore size distribution of less than 10nm. No template with respect to the general ceria sample, leaving the specific surface area ceria state increased. Temperature-programmed tests show that genetic state ceria has higher low oxygen activity is due to its hierarchical structure on the surface area is more conducive to enhance the low-temperature adsorption of oxygen. 2 red maple leaves as a template to prepare Eu-doped silicate genetic state. Eu-doped calcium silicate has left state hierarchy, the micron scale inherited the original red maple leaf morphology, such as vascular bundles, stomata, epidermal cells; at the nanometer scale has three pore distribution. Relative to the no template Eu-doped silicate samples of the general, leaving state Eu-doped silicate surface area, pore volume are greatly increased. A hierarchical structure Eu-doped silicate genetic state of the UV - visible region has a larger light absorption, particularly in the blue-violet light region. Fluorescence tests show that genetic state Eu-doped silicate efficient fluorescence, can be attributed to its hierarchical structure caused by the light absorption efficiency more effectively. 3 biomass (rice, beans) as the nitrogen source of nitrogen-doped ceria. Cerium salt soak through biomass and sintered ceria were prepared. X-ray photoelectron spectroscopy showed that this method can be effectively incorporated in ceria nitrogen. Nitrogen-doped ceria greatly increased oxygen defects, in which nitrogen has played a catalytic role of oxygen defects, including induced lattice distortion, reduce the oxide lattice oxygen vacancy formation energy. With a high concentration of oxygen defects demonstrated nitrogen-doped ceria bulk oxygen reduction process integration to the low temperature reduction curve, which means that the bulk of its activity and oxygen were increased mobility can be attributed to high levels of nitrogen-doped oxygen defects caused by .

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