新型改性银基半导体材料的制备及光催化性能研究

发布时间：2018-07-08 11:56

本文选题：钨酸银 + 碳酸银　；参考：《江苏大学》2017年硕士论文

【摘要】：Ag~+拥有d10全满或者全空的特殊电子结构和具有较宽的可见光吸收范围,且会产生独特的自稳定系统而在光催化领域可作为重要的可见光催化材料。然而银基化合物材料在催化过程中会发生光化学腐蚀而产生银单质,进而降低了光催化活性,限制了其在能源、环境等领域的实际应用。因此寻找有效的方法来改善银基材料的稳定性和催化性能成为了研究的重点。本论文主要从新型催化剂的制备和合成方法上入手,采用不同的方法合成了Ag_2CO_3/AC、Ag_2WO_4/RGO、Ag_2WO_4/WO_3异质结、Ag/Ag_2WO_4/g-C3N4三元等离子体和RGO/ZnFe2O_4/Ag_2WO_4光催化剂,从而提高了银系材料的光催化活性与稳定性。通过FT-IR、UV-Vis、XRD、Raman、SEM、TEM和XPS等表征方法,对样品的结构、形貌、光吸收性质及光催化性能进行了分析。本论文的主要研究内容如下:(1)通过一步简单沉淀法,合成了一系列不同质量比的Ag_2CO_3/AC(Activated carbon)复合材料;将其应用于去除含罗丹明B(RhB)有机染料废水处理,探讨了不同AC含量对复合材料光催化性能的影响。实验结果表明Ag_2CO_3/AC(20%)时,催化材料对RhB的去除效率达到96.6%。并且AC含量为20%的样品的降解速率是纯Ag_2CO_3的10.22倍。(2)通过一步水热法,对Ag_2WO_4进行石墨烯掺杂,以改善其表面结构及物理性能。考察了不同含量的RGO制备的光催化剂的光催化性能。实验结果表明,RGO片层能有效地转移光生电子,抑制Ag_2WO_4的光腐蚀,从而使得复合材料具有更优异的催化活性和稳定性,尤其是样品AR-3具有最好可见光催化活性。(3)首先以水热-酸化-煅烧法合成空心球状的WO_3,通过Ag_2CO_3与WO_3不同比例混合煅烧得到一系列Ag_2WO_4/WO_3异质结复合材料。结果表明,在可见光照射下最高活性可达到94%。并且Ag_2WO_4/WO_3异质结光催化剂显示出优异的稳定性。其动力学反应速率几乎是纯WO_3和Ag_2WO_4的17.0和7.5倍。(4)首先煅烧三聚氰胺得到块状g-C3N4,通过酸化超声得到单层g-C3N4,再通过一步水热合成不同比例的Ag/Ag_2WO_4/g-C3N4三元等离子体催化剂。以RhB或Tetracycline(TC)为目标降解物,研究了Ag/Ag_2WO_4/g-C3N4的光催化活性,结合表征探讨机理。实验结果表明,Ag/Ag_2WO_4均匀分散在g-C3N4纳米片的表面。并且Ag纳米粒子作为电荷分离中心对光催化活性和稳定性起到了重要的作用。复合材料的光催化活性要明显优于g-C3N4和Ag_2WO_4,且动力学常数(0.0125 min-1)高于Ag_2WO_4和Ag/Ag_2WO_4。(5)水热合成纳米球状结构的RGO/ZnFe2O_4,再通过一步共沉淀法合成RGO/ZnFe2O_4/Ag_2WO_4;表征用其结构形态、化学组成、可见光吸收能力和光学性质。采用RhB对其催化性进行评价。结果表明,复合材料比单一样品具有更高的催化能力,其中RGO/ZFO/AWO-2(1:6)催化效率最高(近90%),其动力学常数为0.012 min-1。
[Abstract]:Ag~ has a special electronic structure of d _ (10) full or empty and has a wide range of visible light absorption. It also produces a unique self-stabilization system and can be used as an important visible photocatalytic material in the field of photocatalysis. However, the photochemical corrosion of silver-based compound materials will occur in the process of photochemical corrosion, which will reduce the photocatalytic activity and limit its practical application in the fields of energy, environment and so on. Therefore, to find effective methods to improve the stability and catalytic performance of silver-based materials has become the focus of research. In this paper, the preparation and synthesis methods of new catalysts are discussed, and the Ag2CO3 / AAC / Ag2WO / AW _ 4 photocatalysts have been synthesized by different methods. The photocatalytic activity and stability of Ag / Ag-2WO _ 3N _ 4 ternary plasma and RGO-ZnFe _ 2O _ 4 / Ag _ 2WO _ 4 photocatalysts have been improved by using different methods in the synthesis of Ag2CO3 / AAC / Ag-2WO _ 4 photocatalysts, thus increasing the photocatalytic activity and stability of the Ag / Ag _ 2WO _ 3N _ 4 heterojunction as well as the RGO-ZnFe2O4 / Ag2WO _ 4 photocatalyst. The structure, morphology, photoabsorption properties and photocatalytic properties of the samples were characterized by FTIR UV-Vis-XRDX (XRDX) Ramande SEMU TEM and XPS. The structure, morphology, photoabsorption properties and photocatalytic properties of the samples were analyzed by means of TEM and XPS. The main contents of this thesis are as follows: (1) A series of Ag2CO3 / AC (Activated carbon) composites with different mass ratios have been synthesized by one step simple precipitation method and applied to the treatment of organic dyestuff wastewater containing Rhodamine B (RhB). The effect of different AC content on the photocatalytic properties of composites was discussed. The experimental results show that when Ag2CO3 / AC (20%), the removal efficiency of RhB by the catalytic material reaches 96.6. And the degradation rate of the sample with 20% AC content is 10.22 times that of the pure Ag2COST3. (2) Ag2WO4 is doped with graphene by one step hydrothermal method to improve its surface structure and physical properties. The photocatalytic properties of the photocatalysts prepared by RGO were investigated. The experimental results show that the RGO layer can effectively transfer photogenerated electrons and inhibit the photocorrosion of Ag2WOS _ 4, which makes the composite have better catalytic activity and stability. Especially, the sample AR-3 has the best visible photocatalytic activity. (3) first, hollow spherical WO _ S _ 3s were synthesized by hydrothermal acidification-calcination method, and a series of Ag2WO _ 4 / WO _ 3 heterojunction composites were obtained by calcination of AgStud _ 2CO _ 3 and WO _ S _ 3 in different proportions. The results showed that the highest activity could reach 94g under visible light irradiation. And AgSZ / WO\ +\ {3\}\ ^ 3 heterojunction photocatalysts show excellent stability. The kinetic reaction rate is almost 17.0 and 7.5 times of that of pure WO _ S _ 3 and Ag_ 2WOS _ 4. (4) the bulk g-C _ 3N _ 4 is obtained by calcination of melamine, the monolayer g-C _ 3N _ 4 is obtained by acidizing ultrasound, and then the agg / g _ 2W _ 2W _ 2W _ 2W _ 2W _ 3N _ 4 ternary plasma catalyst is synthesized by one step hydrothermal treatment. With RhB or Tetracycline (TC) as the target degradation material, the photocatalytic activity of Ag / Ag2WOT _ 4 / g-C _ 3N _ 4 was studied and the mechanism was discussed. The experimental results show that Ag / Ag2WO _ 4 is uniformly dispersed on the surface of g-C _ 3N _ 4 nanoparticles. And Ag nanoparticles as charge separation centers play an important role in photocatalytic activity and stability. The photocatalytic activity of the composite is significantly better than that of g-C _ 3N _ 4 and AgS _ 2WO _ 4, and the kinetic constant (0.0125 min-1) is higher than that of Ag2W _ 2W _ 2O _ 4 and AgS _ 2W _ 2O _ 4. (5) hydrothermal synthesis of spherical RGO-ZnFe _ 2O _ 2O _ 4, and synthesis of RGO-ZnFe _ 2O _ 4 / Ag _ 2WO _ 4 by one-step coprecipitation. Visible light absorption capacity and optical properties. RhB was used to evaluate its catalytic properties. The results show that the composite has higher catalytic activity than the single sample, among which RGO / ZFOP AWO-2 (1:6) has the highest catalytic efficiency (nearly 90%), and its kinetic constant is 0.012 min-1.
【学位授予单位】：江苏大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O643.36

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