Synthesis Of One-Dimensional Composite Nanomaterials By Single Sprinkler Electrospinning

Nanomaterials are changing our ways of living and improving the quality of our life. Therefore, the synthesis of novel nanostructures or nanomaterials by simple and controllable methods and their performance have attracted great attention. Electrospinning has much superiority to other methods in synthesizing one-dimensional nanomaterials, such as universality. And more, electrospinning is the only one method to synthesize continuous nanofibers at present. However, electrospinning still faces many challenges in its application for design of nanostructures and novel nanomaterials, such as for one-dimensional complex metal oxides nanomaterials. It’s well known that perovskite oixdes and transition metal oxides have many important applications in photocatalysts, solid oxide fuel cells, supercapacitor and lithium ion battery. In this thesis, one-dimensional complex transition metal oxides nanomaterials with hierachical nanostructures have been synthesized by single sprinkler electrospinning. In addition, their related catalytic performances have been explored. The main results are summarized as follows:1. Synthesis of wire-in-tube Fe2O3 nanofibers, wire-in-tube Mn2O3 nanofibers and nanotubes, and their catalytic performance for the thermal decomposition of ammonium perchlorate (AP)wire-in-tube Mn2O3 nanofibers have been synthesized by single sprinkler electrospinning and temperature programming calcination. The wire-in-tube Mn2O3 nanofibers possess a thickness of tube wall about 10-15nm, with outside diameter of ～250 nm and diameters of wire～50nm. Based on the results of TEM、SEM and etc, we propose a possible formation mechanism of wire-in-tube Mn2O3 nanofibers and Mn2O3 nanotubes, which involves a thermally driven contraction process. During temperature programming calcination, the solvent of deionized water, HAc and ethanol were evaporated and abundant gases were produced along with the decomposition of PVP. Meantime, original inorganic ions began to transform into little seed crystal, which were driven by the gas, migrated along a certain direction and aggregated each other to form wire-in-tube nanofibers and nanotube. The catalytic results indicated that these two kinds of Mn2O3 nanomaterials showed outstanding catalytic performance in thermal decomposition of ammonium perchlorate (AP).Wire-in-tube Fe2O3 nanofibers have also been synthesized by the developed method. The obtained wire-in-tube Fe2O3 nanofibers possess a thickness of tube wall about 10～15 nm, with outside diameter of 120～150 nm and diameters of wire 30～ 50 nm, which indicates that the presented single sprinkler electrospinning combined with temperature programming calcination is universal for synthesizing one-dimensional nanomaterials with complex nanostructures, such as wire-in-tube, nanotube, and etc.2、Synthesis of LaFeO3 mesoporous nanotubes and their catalytic performance for oxygen reduction reaction(ORR)LaFeO3 mesoporous nanotubes have been synthesized by single sprinkler electrospinning and temperature programming calcination. LaFeO3 mesoporous nanotubes possess a high surface area of 33 m2/g and a nanotubular thickness of 10～ 20nm, with outside diameter and inside diameter of 50～70nm and 20～50nm, respectively. For comparison, LaFeO3 mesoporous nanotubes and LaFeO3 nanoparticles were tested for catalyzing oxygen reduction reaction (ORR). The results indicated that LaFeO3 mesoporous nanotubes have much higher activity than LaFeO3 nanoparticles, which may be attributed to the higher specific surface area and the special mesoporous nanotube structure.