【作者】 文伟；

【导师】 吴进明；

【作者基本信息】 浙江大学 ， 材料加工工程， 2014， 博士

【摘要】 传质和界面电荷传输是能量存储、气敏、催化等应用领域的关键科学问题。多孔材料可提供大的比表面积和丰富的传质通道,应用于上述领域时表现出优异的性能。然而,目前绝大多数制备多孔材料的方法均依赖于模板的辅助,制备过程复杂、能耗高、周期长。另外,常规模板法对许多因素敏感,因而对操作环境和操作要求高,进一步增加了制备成本。因此,发展一些简单、快速、低成本制备多孔材料的方法具有十分重要的科学意义和实际应用价值。溶液燃烧法是一种简单的制备金属氧化物的方法,利用反应自身释放的热量维持反应的进行,因而具有节能、快速的优点,成为低成本制备方法的理想选择之一。但现有溶液燃烧存在“燃烧过程可控性差”和“产物形貌可控性差”两大缺点。针对上述缺点,本文主要致力于对溶液燃烧过程的改性。同时,以高性能功能材料研发为导向,设计一些具有特殊纳米结构的多孔过渡金属氧化物粉末。论文基于溶液燃烧过程发展了一些全新的简单、快速、无模板、低成本制备多孔过渡金属氧化物粉末的通用方法,所得到的材料用于锂离子电池、气体传感器、催化剂时表现出优异的性能。主要研究结果有：(1)采用溶液燃烧法结合后续热处理制备了单相La4Ni3O10层状钙钛矿粉末,后续热处理所需温度和时间均低于其他制备技术,充分展示了溶液燃烧法制备难合成物质的优势。研究发现,La4Ni3O10粉末在常温常压、无光照条件下即可降解有机染料废水。(2)针对溶液燃烧的燃烧模式难以控制和改变的特点,通过在适当的反应体系中添加NaF控制燃烧模式,研发了一种全新的燃烧模式——喷发燃烧。这种喷发燃烧过程得到的产物具有疏松多孔的结构,应用于锂离子电池负极时具有比传统溶液燃烧所得材料更优异的性能。该燃烧模式具有较好的通用性,可应用于Ni-O、Ni-Co-O、Co-O、La-O、Ni-Co-O、Zn-Co-O、La-Ni-O等氧化物体系。(3)在络合物燃烧／分解体系中,以水合肼作为燃料和络合剂,以硝酸盐为氧化剂,额外引入醋酸盐作为气化剂,研发了一种一步燃烧合成大孔金属氧化物的通用技术,在该制备过程中多孔结构和氧化物的晶格一步形成,不需要模板／表面活性剂,制备过程简单快速。产物的孔结构、孔尺寸分布及整体框架结构(二维或三维结构)可控。制备的大孔NiO/Ni作为锂离子电池负极时具有优异的电化学性能；制备的珊瑚状大孔／介孔多级结构ZnO具有优异的气敏特性。(4)通过选择适当的燃料和控制燃料／硝酸盐的比例,可大大降低燃烧的剧烈程度,得到一种非晶的金属络合物。将该络合物在空气中热处理或室温下与双氧水反应,可以得到高比表面积的、具有一定纳米结构的多孔过渡金属氧化物,其孔结构和整体框架形貌可控。作为锂离子电池负极材料时,制备的多孔C0304和锐钛矿TiO2超薄纳米带都具有优异的性能；制备的多孔ZnO也具备优异的气敏性能。更多还原

【Abstract】 Mass transport and charge transfer (especially at the interface) are two key factors in various applications of energy storage, gas sensor, and catalysis. Porous materials are the right choice for the applications above-mentioned, because they are able to provide large surface area and abundant channels. Up to now, most approaches to porous materials focus on template-assisted methods, including hard templates and soft templates. The template-assisted routes are complex and high cost. It is therefore of general interest to produce porous materials with simple and economical synthesis strategies.Solution combustion synthesis (SCS), which is self-sustained by its own exothermic reaction, is an effective, rapid, and energy-efficient method for mass productions of various metal oxides. Unfortunately, it is difficult to control the combustion process and morphology of product in SCS. In the current investigation, the two major shortcomings inherent of the SCS were focused on, through careful modifications of the combustion procedure. Several porous metal oxides with special nanofeatures via SCS were achieved for high performance functional applications. Several novel, simple, template-free, low-cost, and universal synthesis routes based on SCS were developed for mass fabrications of porous metal oxides, which possessed excellent properties arising from the unique structures when utilized for surface-relative applications of Li-ion batteries and gas sensors.It is difficult to achieve phase-pure La4Ni3010by existing synthesis methods because of the easy coexistence of several other phases encountered in the La-Ni-O system. Phase-pure layered perovskite La4Ni3010powders were synthesized by a solution combustion approach combined with a subsequent heat treatment at1000℃for3h, which demonstrated the superiority of SCS in synthesis of complex oxides. It is found that, in the presence of the LaNia3O10powders, aqueous dyes can be degraded catalytically and efficiently under ambient conditions. Neither light nor additional reagents are needed in the current reaction. A series of chemical and electrochemical experiments suggested that the dye degradation proceeds through electron transfers from the dye molecules to the catalyst and then to electron acceptors such as dissolved oxygen.In nature, volcano eruptions create large amounts of porous volcano ashes within a short duration. Inspired by such phenomena, we reported our first attempt to achieve an artificial volcano for mass productions of various oxide nanoparticles with enhanced properties for energy and environmental applications. The introduction of NaF into the SCS resulted in the formation of porous structures. The novel eruption combustion pattern observed in SCS provides a versatile alternative for SCS to control combustion behavior, microstructure, and property of the products. NiO/Ni nanocomposite yielded by the new approach exhibited a good dye-absorption ability. When utilized as anode materials for lithium-ion batteries, excellent electrochemical performances were also achieved. The new SCS pattern is versatile, emerging in various systems of Ni-Co-O, Co-O, La-O, Ni-Co-O, Zn-Co-O, and La-Ni-O.Macroporous metal oxides were achieved in a flash by the direct decomposition/combustion of a metal complex, through mainly the additive of acetate salts as gasfication agents. The fabrication route is template-free, surfactant-free, and highly effective. Taking NiO/Ni as an example, the metal complex was achieved by simply mixing nickel acetate, nickel nitrate, hydrazine hydrate, and glycine in water. The pore size, porosity, and even morphology of the porous NiO/Ni network (three-or two-dimensional architectures) can be conveniently tuned by adjusting the composition of the complex. This synthesis route can be extended to prepare other macroporous metal oxides, such as ZnO. The achieved macroporous NiO/Ni possessed excellent electrochemical performance and the coral-like hierarchical macro/meso-porous ZnO also exhibited excellent gas-sensing performance.Amorphous metal complexes were prepared by SCS applying a high fuel/oxidizer ratio, which greatly reduced the violent combustion, improving the safety of SCS. Thermal treatments of the complex in air or reactions of the complex with H2O2resulted in the formation of porous metal oxides with high specific surface area. Both the achieved porous Co3O4and the TiO2nanobelts exhibited excellent performance in anodes of lithium ion batteries. The achieved macroporous ZnO possessed ideal gas sensing properties.更多还原