季銨類羧酸鹽在層狀氫氧化鋅及氧化鋅水熱合成中的研究
發(fā)布時(shí)間：2018-07-28 17:39
【摘要】：氧化鋅是公認(rèn)的最重要、最有發(fā)展前途的一種納米半導(dǎo)體材料,它被廣泛應(yīng)用于光學(xué)、電學(xué)、催化劑等眾多領(lǐng)域。氧化鋅的合成方法多種多樣,通過鋅鹽前體在水熱環(huán)境下直接合成或者合成氫氧化鋅鹽再煅燒,是常用的一種高效、環(huán)保的工藝,受到人們的廣泛關(guān)注。因而研究鋅鹽在水熱反應(yīng)中的轉(zhuǎn)變路徑對(duì)于更好的用水熱法制備納、微米氧化鋅有著重要的指導(dǎo)意義。由于鋅鹽在水熱合成中晶核生成過快,傳統(tǒng)的生長(zhǎng)觀點(diǎn)認(rèn)為無論是氫氧化鋅鹽還是氧化鋅在水熱合成中幾乎都是成核后熟化的過程。然而隨著研究的深入,人們發(fā)現(xiàn)水熱合成中晶體生長(zhǎng)經(jīng)歷的路徑遠(yuǎn)比預(yù)想的復(fù)雜,熟化過程往往是末期現(xiàn)象。在熟化以前,存在著多種轉(zhuǎn)變的路徑,而控制這些路徑將對(duì)氧化鋅最終形貌的形成有著決定性的影響。本文通過在水熱合成中引入了一系列可溶性長(zhǎng)鏈季銨類羧酸鋅鹽,有效的調(diào)節(jié)了水熱反應(yīng)進(jìn)程,合成了一系列具有新穎形貌的氧化鋅�？疾炝瞬煌庪x子對(duì)最終形貌的影響,更重要的是發(fā)現(xiàn)了鋅鹽在水熱中轉(zhuǎn)變的一些新路徑和轉(zhuǎn)變過程的新證據(jù)。具體工作如下：1、以合成的長(zhǎng)鏈可溶性季銨類羧酸溴鋅鹽作為前體,尿素作堿式劑,在水熱105℃C條件下通過控制反應(yīng)時(shí)間合成了一系列具有獨(dú)特形貌的層狀氫氧化鋅,并在600℃C將其煅燒得到了具有相應(yīng)形貌的氧化鋅。在水熱合成過程中發(fā)現(xiàn)了兩種不同晶型的層狀氫氧化鋅的轉(zhuǎn)變過程：反應(yīng)初期是一種類似于羧酸類氫氧化鋅鹽晶型的產(chǎn)物,產(chǎn)物的層與層之間充滿了長(zhǎng)鏈和碳酸根；而反應(yīng)后期,其表現(xiàn)出的晶型與堿式碳酸鋅一致,層間只含有碳酸根。這和以往認(rèn)為鋅鹽在水熱條件下只能形成單一晶型的層狀氫氧化鋅有著明顯的不同。通過對(duì)比不同濃度的數(shù)據(jù),發(fā)現(xiàn)溶液中存在足量的長(zhǎng)鏈基團(tuán)是完成以上晶型轉(zhuǎn)變的必要條件。這清晰地說明,引起晶型的轉(zhuǎn)變的根本原因是長(zhǎng)鏈的插入和脫出。伴隨長(zhǎng)鏈的插入和脫出,層狀氫氧化鋅的形貌也隨之改變。而這些不同形貌的層狀氫氧化鋅可作為自我模板煅燒得到不同形貌的氧化鋅,對(duì)單一鋅鹽形成多種形貌的氧化鋅的制備方法起到有益的補(bǔ)充。2、以合成的長(zhǎng)鏈可溶性季銨類羧酸溴鋅鹽作為前體,六次甲基四胺作為堿式劑,在水熱105℃C條件下合成氧化鋅。在合成過程中獲得了一種具有獨(dú)特形貌的頭部是微球狀層狀堿式鋅鹽軀干是氧化鋅棒的二元晶型共生體。在合成氧化鋅的水熱過程中,傳統(tǒng)的觀點(diǎn)認(rèn)為氧化鋅在水相中是消溶再成核為主的轉(zhuǎn)變過程,而固相轉(zhuǎn)變是僅僅發(fā)生在煅燒過程中的。通過對(duì)共生體的分析,發(fā)現(xiàn)了層狀堿式鋅鹽到氧化鋅的拓?fù)渥兓?表明了固相轉(zhuǎn)變?cè)谒芤褐邪l(fā)生的合理性。通過精確控制反應(yīng)時(shí)間和反應(yīng)物濃度,發(fā)現(xiàn)了在氧化鋅水熱合成中消溶再成核和固相轉(zhuǎn)變存在著明顯的競(jìng)爭(zhēng)關(guān)系,而適當(dāng)?shù)拈L(zhǎng)鏈濃度和六次甲基四胺濃度可以有效平衡這種關(guān)系。在合適濃度下可以完成從鋅鹽→層狀堿式鋅鹽→層狀堿式鋅鹽/氧化鋅共生體→氧化鋅的固相轉(zhuǎn)變過程。共生體的出現(xiàn)為氧化鋅在水相合成中由中間體經(jīng)歷固相轉(zhuǎn)變形成提供了最直接的證據(jù),對(duì)探索水相合成氧化鋅路徑有著重要幫助。同時(shí)合成過程中出現(xiàn)的一系列3D形貌的層狀堿式鋅鹽,通過煅燒也得到了更多新穎形貌的3D氧化鋅。3、以合成的長(zhǎng)鏈可溶性季銨類羧酸氯鋅鹽作為前體,六次甲基四胺作為堿式劑,在水熱105℃條件下合成氧化鋅。在合成過程中發(fā)現(xiàn)了一種單分散的具有3D多層結(jié)構(gòu)的Zn5(OH)8Cl2·H2O中間體,而傳統(tǒng)以普通無機(jī)鋅鹽為前體合成的這種化合物通常是無序堆積的2D納/微米片。通過梯次增加溶液中含有的陰離子種類,如醋酸根、氯離子、長(zhǎng)鏈季銨基團(tuán),發(fā)現(xiàn)Zn5(OH)8Cl2·H2O的形貌由單層2D微米片逐漸轉(zhuǎn)變?yōu)?D多層結(jié)構(gòu),證明了均一單分散的3D多層結(jié)構(gòu)的形成是長(zhǎng)鏈季銨類羧酸鹽含有的豐富離子基團(tuán)共同作用的結(jié)果,表明了這種新穎的羧酸鹽對(duì)于合成的3D形貌的層狀氫氧化鋅有著獨(dú)特優(yōu)勢(shì)。此外該3D多層結(jié)構(gòu)因其獨(dú)特的形貌從而具有更高的比表面積(44.57 m~2g~(-1)),遠(yuǎn)遠(yuǎn)高于氯化鋅為前體制備的單層2D的Zn5(OH)8Cl2·H2O微米片(21.74 m~2g~(-1))。并且與2D微米片相比,3D多層結(jié)構(gòu)在超級(jí)電容器中表現(xiàn)出更優(yōu)異的電化學(xué)性能,無論是儲(chǔ)容能力、倍率性能還是循環(huán)穩(wěn)定性均得到大幅提高。在電流密度5 Ag~(-1)下可獲得高達(dá)240 Fg~(-1)的比電容,相對(duì)于單層2D微米片提高了約40%,循環(huán)2000圈后初始電容保持率為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.
【學(xué)位授予單位】：東南大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2016
【分類號(hào)】：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.
【學(xué)位授予單位】：東南大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2016
【分類號(hào)】：TQ132.41;TM53
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