季铵类羧酸盐在层状氢氧化锌及氧化锌水热合成中的研究
发布时间：2018-07-28 17:39
【摘要】：氧化锌是公认的最重要、最有发展前途的一种纳米半导体材料,它被广泛应用于光学、电学、催化剂等众多领域。氧化锌的合成方法多种多样,通过锌盐前体在水热环境下直接合成或者合成氢氧化锌盐再煅烧,是常用的一种高效、环保的工艺,受到人们的广泛关注。因而研究锌盐在水热反应中的转变路径对于更好的用水热法制备纳、微米氧化锌有着重要的指导意义。由于锌盐在水热合成中晶核生成过快,传统的生长观点认为无论是氢氧化锌盐还是氧化锌在水热合成中几乎都是成核后熟化的过程。然而随着研究的深入,人们发现水热合成中晶体生长经历的路径远比预想的复杂,熟化过程往往是末期现象。在熟化以前,存在着多种转变的路径,而控制这些路径将对氧化锌最终形貌的形成有着决定性的影响。本文通过在水热合成中引入了一系列可溶性长链季铵类羧酸锌盐,有效的调节了水热反应进程,合成了一系列具有新颖形貌的氧化锌。考察了不同阴离子对最终形貌的影响,更重要的是发现了锌盐在水热中转变的一些新路径和转变过程的新证据。具体工作如下：1、以合成的长链可溶性季铵类羧酸溴锌盐作为前体,尿素作碱式剂,在水热105℃C条件下通过控制反应时间合成了一系列具有独特形貌的层状氢氧化锌,并在600℃C将其煅烧得到了具有相应形貌的氧化锌。在水热合成过程中发现了两种不同晶型的层状氢氧化锌的转变过程：反应初期是一种类似于羧酸类氢氧化锌盐晶型的产物,产物的层与层之间充满了长链和碳酸根；而反应后期,其表现出的晶型与碱式碳酸锌一致,层间只含有碳酸根。这和以往认为锌盐在水热条件下只能形成单一晶型的层状氢氧化锌有着明显的不同。通过对比不同浓度的数据,发现溶液中存在足量的长链基团是完成以上晶型转变的必要条件。这清晰地说明,引起晶型的转变的根本原因是长链的插入和脱出。伴随长链的插入和脱出,层状氢氧化锌的形貌也随之改变。而这些不同形貌的层状氢氧化锌可作为自我模板煅烧得到不同形貌的氧化锌,对单一锌盐形成多种形貌的氧化锌的制备方法起到有益的补充。2、以合成的长链可溶性季铵类羧酸溴锌盐作为前体,六次甲基四胺作为碱式剂,在水热105℃C条件下合成氧化锌。在合成过程中获得了一种具有独特形貌的头部是微球状层状碱式锌盐躯干是氧化锌棒的二元晶型共生体。在合成氧化锌的水热过程中,传统的观点认为氧化锌在水相中是消溶再成核为主的转变过程,而固相转变是仅仅发生在煅烧过程中的。通过对共生体的分析,发现了层状碱式锌盐到氧化锌的拓扑变化,表明了固相转变在水溶液中发生的合理性。通过精确控制反应时间和反应物浓度,发现了在氧化锌水热合成中消溶再成核和固相转变存在着明显的竞争关系,而适当的长链浓度和六次甲基四胺浓度可以有效平衡这种关系。在合适浓度下可以完成从锌盐→层状碱式锌盐→层状碱式锌盐/氧化锌共生体→氧化锌的固相转变过程。共生体的出现为氧化锌在水相合成中由中间体经历固相转变形成提供了最直接的证据,对探索水相合成氧化锌路径有着重要帮助。同时合成过程中出现的一系列3D形貌的层状碱式锌盐,通过煅烧也得到了更多新颖形貌的3D氧化锌。3、以合成的长链可溶性季铵类羧酸氯锌盐作为前体,六次甲基四胺作为碱式剂,在水热105℃条件下合成氧化锌。在合成过程中发现了一种单分散的具有3D多层结构的Zn5(OH)8Cl2·H2O中间体,而传统以普通无机锌盐为前体合成的这种化合物通常是无序堆积的2D纳/微米片。通过梯次增加溶液中含有的阴离子种类,如醋酸根、氯离子、长链季铵基团,发现Zn5(OH)8Cl2·H2O的形貌由单层2D微米片逐渐转变为3D多层结构,证明了均一单分散的3D多层结构的形成是长链季铵类羧酸盐含有的丰富离子基团共同作用的结果,表明了这种新颖的羧酸盐对于合成的3D形貌的层状氢氧化锌有着独特优势。此外该3D多层结构因其独特的形貌从而具有更高的比表面积(44.57 m~2g~(-1)),远远高于氯化锌为前体制备的单层2D的Zn5(OH)8Cl2·H2O微米片(21.74 m~2g~(-1))。并且与2D微米片相比,3D多层结构在超级电容器中表现出更优异的电化学性能,无论是储容能力、倍率性能还是循环稳定性均得到大幅提高。在电流密度5 Ag~(-1)下可获得高达240 Fg~(-1)的比电容,相对于单层2D微米片提高了约40%,循环2000圈后初始电容保持率为97.1%。
[Abstract]:Zinc Oxide is recognized as the most important and promising nanometer semiconductor material. It is widely used in many fields, such as optics, electricity, catalyst and so on. The synthetic methods of Zinc Oxide are varied. The synthesis or synthesis of zinc hydroxide by zinc salt precursor in the hydrothermal environment is a kind of efficient and environmentally friendly industry. Art has attracted wide attention. Therefore, it is of great significance to study the transformation path of zinc salt in hydrothermal reaction. It is of great guiding significance for a better hydrothermal method to prepare nano Zinc Oxide. Due to the rapid formation of MICROTEK nucleation in hydrothermal synthesis of zinc salts, the traditional growth point of view is that zinc hydroxide or Zinc Oxide is a few in hydrothermal synthesis. All of them are the process of maturation after nucleation. However, with the deepening of research, people find that the path of crystal growth in hydrothermal synthesis is far more complex than expected, and the process of maturation is often the end stage. There are many ways of transformation before maturation, and the control of these paths will have a decisive shadow on the formation of the final morphology of Zinc Oxide. By introducing a series of soluble long chain quaternary ammonium carboxylate salts in hydrothermal synthesis, this paper effectively regulates the process of hydrothermal reaction and syntheses a series of Zinc Oxide with novel morphologies. The influence of different anions on the final morphology is investigated. More importantly, some new paths and changes of the transformation of zinc salt in water heat are found. The new evidence of the process is as follows: 1, a series of layered zinc hydroxide with unique morphology was synthesized with the synthesized long chain soluble quaternary ammonium carboxylic carboxylic acid bromide as precursor and urea as the alkali agent under the condition of water heat 105 C, and the Zinc Oxide with corresponding morphologies was calcined at 600 C. In the process of hydrothermal synthesis, the transformation process of two different crystalline forms of layered zinc hydroxide was found. At the beginning of the reaction, it was a product similar to the crystal of the carboxylic zinc hydroxide. The layer and the layer of the product were full of long chains and carbonates, while in the late reaction, the crystalline form was consistent with the alkaline zinc carbonate, and the interlayer only contained carbonic acid. This is obviously different from that of zinc hydroxide, which can only form a single crystalline form of zinc hydroxide in the hydrothermal condition. By comparing the data of different concentrations, it is found that the existence of sufficient long chain groups in the solution is a necessary condition for the completion of the above crystalline transition. This clearly indicates that the root cause of the transformation of the crystal is long chain. The morphology of layered zinc hydroxide changes with the insertion and removal of long chains. The layered zinc hydroxide with different morphologies can be calcined as a self template to obtain different morphologies of Zinc Oxide, and a useful supplement to the preparation method of a single zinc salt for the formation of a variety of morphologies of Zinc Oxide is beneficial to the synthesis of long chain soluble Zinc Oxide. The quaternary ammonium carboxylic acid bromide salts are used as precursors and six times methyl four amine as a basic agent to synthesize Zinc Oxide under the condition of water heat 105 C. In the process of synthesis, a kind of unique morphology of the head is a microspheric layered alkaline zinc salt trunk is a two yuan crystalline symbiosis of the Zinc Oxide rod. In the hydrothermal process of synthesizing Zinc Oxide, it is traditional. The point of view is that Zinc Oxide is a process of digestion and re nucleation in the water phase, and the solid phase transition is only during the calcination process. Through the analysis of the symbionts, the topological change of the layered alkaline zinc salt to the Zinc Oxide is found, which shows the rationality of the formation of the solid phase transition in the aqueous solution. It is found that there is a significant competitive relationship between the dissolution renucleation and the solid phase transformation in Zinc Oxide hydrothermal synthesis, and the proper long chain concentration and the concentration of six times methyl four amine can effectively balance this relationship. At the appropriate concentration, the zinc salt, layered alkaline zinc salt, layered alkaline zinc salt / Zinc Oxide symbiont, and oxygen can be completed at the appropriate concentration. The emergence of the symbionts provides the most direct evidence for the formation of the solid phase transition from the intermediates to the Zinc Oxide in the water phase synthesis, which is of great help to the exploration of the path of the water phase synthesis of the Zinc Oxide. At the same time, a series of 3D morphologies of the alkaline zinc salts, which appear in the process of synthesis, have been more new by calcination. The glume morphology of 3D Zinc Oxide.3 is used to synthesize long chain soluble quaternary ammonium carboxylic acid chloride as precursor and six times methyl four amine as a basic agent to synthesize Zinc Oxide under the condition of hydrothermal 105. A monodisperse Zn5 (OH) 8Cl2. H2O intermediate with 3D multilayer structure is found, while conventional inorganic zinc salts are used as precursors. This compound is usually a disordered 2D nano / micron. By increasing the number of anions contained in the solution, such as acetate, chloride, and long chain quaternary ammonium groups, the morphology of Zn5 (OH) 8Cl2. H2O is gradually transformed from single layer 2D micron to 3D multilayer, which proves that the formation of homogeneous monodisperse 3D multilayer structure is long chain The results of the interaction of the rich ionic groups containing the Quaternary carboxylates show that this novel carboxylate has a unique advantage in the synthesis of 3D morphologies of layered zinc hydroxide. In addition, the 3D multilayer structure has a higher specific surface area (44.57 m~2g ~ (-1)) because of its unique morphology, which is far higher than the preparation of zinc chloride for the former system. The single layer 2D Zn5 (OH) 8Cl2. H2O micron (21.74 m~2g~ (-1)). And compared with the 2D micron, the 3D multilayer structure shows excellent electrochemical performance in the supercapacitor. The capacity of the storage, the multiplication and the cycle stability are greatly improved. The specific capacitance of up to 240 Fg~ is obtained under the electric current density of 5 Ag~ (-1). For monolayer 2D microchip, the capacitance is increased by about 40%, and the initial capacitance retention rate is 97.1%. after 2000 cycles.
【学位授予单位】：东南大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TQ132.41;TM53
[Abstract]:Zinc Oxide is recognized as the most important and promising nanometer semiconductor material. It is widely used in many fields, such as optics, electricity, catalyst and so on. The synthetic methods of Zinc Oxide are varied. The synthesis or synthesis of zinc hydroxide by zinc salt precursor in the hydrothermal environment is a kind of efficient and environmentally friendly industry. Art has attracted wide attention. Therefore, it is of great significance to study the transformation path of zinc salt in hydrothermal reaction. It is of great guiding significance for a better hydrothermal method to prepare nano Zinc Oxide. Due to the rapid formation of MICROTEK nucleation in hydrothermal synthesis of zinc salts, the traditional growth point of view is that zinc hydroxide or Zinc Oxide is a few in hydrothermal synthesis. All of them are the process of maturation after nucleation. However, with the deepening of research, people find that the path of crystal growth in hydrothermal synthesis is far more complex than expected, and the process of maturation is often the end stage. There are many ways of transformation before maturation, and the control of these paths will have a decisive shadow on the formation of the final morphology of Zinc Oxide. By introducing a series of soluble long chain quaternary ammonium carboxylate salts in hydrothermal synthesis, this paper effectively regulates the process of hydrothermal reaction and syntheses a series of Zinc Oxide with novel morphologies. The influence of different anions on the final morphology is investigated. More importantly, some new paths and changes of the transformation of zinc salt in water heat are found. The new evidence of the process is as follows: 1, a series of layered zinc hydroxide with unique morphology was synthesized with the synthesized long chain soluble quaternary ammonium carboxylic carboxylic acid bromide as precursor and urea as the alkali agent under the condition of water heat 105 C, and the Zinc Oxide with corresponding morphologies was calcined at 600 C. In the process of hydrothermal synthesis, the transformation process of two different crystalline forms of layered zinc hydroxide was found. At the beginning of the reaction, it was a product similar to the crystal of the carboxylic zinc hydroxide. The layer and the layer of the product were full of long chains and carbonates, while in the late reaction, the crystalline form was consistent with the alkaline zinc carbonate, and the interlayer only contained carbonic acid. This is obviously different from that of zinc hydroxide, which can only form a single crystalline form of zinc hydroxide in the hydrothermal condition. By comparing the data of different concentrations, it is found that the existence of sufficient long chain groups in the solution is a necessary condition for the completion of the above crystalline transition. This clearly indicates that the root cause of the transformation of the crystal is long chain. The morphology of layered zinc hydroxide changes with the insertion and removal of long chains. The layered zinc hydroxide with different morphologies can be calcined as a self template to obtain different morphologies of Zinc Oxide, and a useful supplement to the preparation method of a single zinc salt for the formation of a variety of morphologies of Zinc Oxide is beneficial to the synthesis of long chain soluble Zinc Oxide. The quaternary ammonium carboxylic acid bromide salts are used as precursors and six times methyl four amine as a basic agent to synthesize Zinc Oxide under the condition of water heat 105 C. In the process of synthesis, a kind of unique morphology of the head is a microspheric layered alkaline zinc salt trunk is a two yuan crystalline symbiosis of the Zinc Oxide rod. In the hydrothermal process of synthesizing Zinc Oxide, it is traditional. The point of view is that Zinc Oxide is a process of digestion and re nucleation in the water phase, and the solid phase transition is only during the calcination process. Through the analysis of the symbionts, the topological change of the layered alkaline zinc salt to the Zinc Oxide is found, which shows the rationality of the formation of the solid phase transition in the aqueous solution. It is found that there is a significant competitive relationship between the dissolution renucleation and the solid phase transformation in Zinc Oxide hydrothermal synthesis, and the proper long chain concentration and the concentration of six times methyl four amine can effectively balance this relationship. At the appropriate concentration, the zinc salt, layered alkaline zinc salt, layered alkaline zinc salt / Zinc Oxide symbiont, and oxygen can be completed at the appropriate concentration. The emergence of the symbionts provides the most direct evidence for the formation of the solid phase transition from the intermediates to the Zinc Oxide in the water phase synthesis, which is of great help to the exploration of the path of the water phase synthesis of the Zinc Oxide. At the same time, a series of 3D morphologies of the alkaline zinc salts, which appear in the process of synthesis, have been more new by calcination. The glume morphology of 3D Zinc Oxide.3 is used to synthesize long chain soluble quaternary ammonium carboxylic acid chloride as precursor and six times methyl four amine as a basic agent to synthesize Zinc Oxide under the condition of hydrothermal 105. A monodisperse Zn5 (OH) 8Cl2. H2O intermediate with 3D multilayer structure is found, while conventional inorganic zinc salts are used as precursors. This compound is usually a disordered 2D nano / micron. By increasing the number of anions contained in the solution, such as acetate, chloride, and long chain quaternary ammonium groups, the morphology of Zn5 (OH) 8Cl2. H2O is gradually transformed from single layer 2D micron to 3D multilayer, which proves that the formation of homogeneous monodisperse 3D multilayer structure is long chain The results of the interaction of the rich ionic groups containing the Quaternary carboxylates show that this novel carboxylate has a unique advantage in the synthesis of 3D morphologies of layered zinc hydroxide. In addition, the 3D multilayer structure has a higher specific surface area (44.57 m~2g ~ (-1)) because of its unique morphology, which is far higher than the preparation of zinc chloride for the former system. The single layer 2D Zn5 (OH) 8Cl2. H2O micron (21.74 m~2g~ (-1)). And compared with the 2D micron, the 3D multilayer structure shows excellent electrochemical performance in the supercapacitor. The capacity of the storage, the multiplication and the cycle stability are greatly improved. The specific capacitance of up to 240 Fg~ is obtained under the electric current density of 5 Ag~ (-1). For monolayer 2D microchip, the capacitance is increased by about 40%, and the initial capacitance retention rate is 97.1%. after 2000 cycles.
【学位授予单位】：东南大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TQ132.41;TM53
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