摘要石墨烯的制备、表征及石墨烯/氧化锌光催化剂的制备与性能研究石墨烯(Graphene,GR)自从2004年被发现以来,因其理想的二维晶体结构和独特的物理性能而成为研究的热点。
目前,石墨烯的制备方法主要有:微机械剥离法、化学气相沉积法、外延生长法、氧化石墨烯(Graphene Oxide,GO)溶液还原法。
与其它方法相比,氧化石墨烯溶液还原法具有高产量、低成本和可规模化制备等特点,有望成为规模化制备石墨烯的有效途径之一。
然而在还原过程中常采用的还原剂肼和水合肼具有易爆炸性和强毒性,易对环境造成危害。
因此,需要发现一种环境友好、温和且有效的方法来实现化学还原氧化石墨烯(Chemically Reduced Graphene Oxide,CRGO)的批量制备。
氧化锌(ZnO)因其无毒、成本低等优点被广泛应用于光催化的研究。
氧化锌光催化剂光生电子-空穴对的快速复合是氧化锌光催化性能的主要限制因素之一,而石墨烯归因于其良好的电子传输性能和巨大的比表面积,使其成为氧化锌复合改性的理想材料。
本论文的研究内容及结果如下:(1)通过简化的Hummers 法,改进的Hummers 法,加压氧化法三种不同方法制备出了氧化石墨烯。
利用X射线衍射(XRD)、X射线光电子能谱(XPS)、扫描电镜(SEM) 、透射电镜(TEM)、红外光谱(FT-IR)对其化学组成和形貌进行了表征和分析。
结果表明改进的Hummers 方法制备出的氧化石墨烯的具有较高的氧化程度。
(2)在水溶液中,采用具有较强还原能力和环境友好的还原剂腐植酸钠(Sodium Humate, SH)将氧化石墨烯的含氧基团成功移除,制备出稳定均匀的化学还原氧化石墨烯悬浮溶液,碳氧原子比达到3.78。
这种制备方法不仅避免了有毒有害的还原剂以及表面活性剂等的添加和使用,也为化学还原氧化石墨烯的批量制备提供了一种简单且环境友好的方法。
(3)通过水热制备出石墨烯/氮掺杂氧化锌复合光催化材料,最佳的制备条件是氮掺杂量为0.4 g,氧化石墨烯和氮掺杂氧化锌的质量比为5%,水热温度为120 °C。
在此条件下制备出的石墨烯/氮掺杂氧化锌复合光催化材料经过90 min 的光催化反应,亚甲基蓝的降解效率能达到95%。
关键词:石墨烯,氧化锌,腐植酸钠,光催化,亚甲基蓝AbstractThe Preparation and Characterization of Reduced Graphene Oxide and Preparation and Photocatalytic Propertiesof Graphene-ZnO PhotocatalystSince the discovery of graphene in 2004, it has become a hot research topic because of its ideal two-dimensional crystal structure and unique physical properties. Up to now, there are several graphene preparation methods, such as micromechanical exfoliation, chemical vapour deposition, epitaxial growth method and the reduction of graphene oxide solution. The reduction of graphene oxide solution has some advantages compared with other approaches, including large-scale yield, low cost and easy processing, and expected to be an effective way for large-scale preparation of graphene. However, the reducing agent hydrazine hydrate and hydrazine often used in the reduction process is explosive and toxic, easy to cause damage to the environment. Therefore, there is a need for an environmentally friendly, gentle and effective method to achieve the bulk preparation of chemically reduced graphene oxide.(1) Graphene oxide was prepared by simplified Hummers method, modified Hummers method and pressurized oxidation method. The chemical composition and morphology were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy and Fourier transform infrared spectroscopy. The results show that the modified Hummers method has a high degree of oxidation.(2) In the aqueous solution, the oxygen-containing group of graphene oxide was successfully removed by the reducing agent sodium humate, with strong reducing ability and environment friendly, and prepared stable and homogeneous chemically reduced graphene oxide suspension solution with the ratio of carbon to oxygen to 3.78. This preparation not only avoids the addition and use of toxic and harmful reducing agents and surfactants, but also provides a simple and environmentally friendly method for batch preparation of chemically reduced graphene oxide.(3) The graphene/nitrogen-doped zinc oxide composite photocatalyst was prepared by hydrothermal method. The optimum preparation conditions were as follows: thenitrogen doping amount was 0.4 g, the mass ratio of graphene oxide and nitrogen-doped zinc oxide was 5%, the hydrothermal temperature was at 120 °C. The photocatalytic activity of the as-prepared composite photocatalyst can reach 95% after 90 min photocatalytic reaction.Keywords:Chemically Reduced Graphene Oxide, ZnO, sodium humate, photocatalytic, methylene blue目录第1章绪论 (1)1.1石墨烯的结构与性质 (1)1.1.1结构特征 (1)1.1.2电学性质 (1)1.1.3力学性质 (2)1.1.4热学性质 (2)1.1.5光学性质 (2)1.2石墨烯的制备方法 (2)1.2.1微机械剥离法 (2)1.2.2化学气相沉积法 (3)1.2.3外延生长法 (3)1.2.4 GO溶液还原法 (3)1.3石墨烯的应用 (4)1.3.1场效应晶体管 (4)1.3.2传感器 (4)1.3.3储能材料 (5)1.3.4复合材料 (5)1.4石墨烯/氧化锌复合光催化材料的研究进展 (6)1.5研究意义和研究内容 (7)1.5.1研究意义 (7)1.5.2研究内容 (8)第2章实验方法 (9)2.1实验试剂 (9)2.2实验仪器 (9)2.3样品表征方法 (10)2.3.1 X射线衍射(XRD)的测定 (10)2.3.2透射电子显微镜扫描(TEM)的测定 (10)2.3.3扫描电子显微镜扫描(SEM)的测定 (10)2.3.4拉曼光谱(Raman)的测定 (10)2.3.5紫外吸收漫反射(UV-vis)的测定 (10)2.3.6 X射线光电子能谱(XPS)的测定 (10)2.3.7傅式转换红外线光谱(FT-IR)的测定 (11)2.4光催化降解实验 (11)2.4.1光降解实验装置 (11)2.4.2光降解实验方法 (11)第3章化学还原氧化石墨烯的制备及表征 (13)3.1 GO的制备 (14)3.2 GO的结构表征 (15)3.2.1 XRD分析 (15)3.2.2 XPS分析 (15)3.2.3 SEM分析 (16)3.2.4 TEM分析 (17)3.2.5 FT-IR分析 (17)3.3 CRGO的制备 (18)3.3.1温度对CRGO制备的影响 (18)3.3.2 SH用量对CRGO制备的影响 (18)3.3.3反应温度的选择 (19)3.3.4 SH用量的优化 (19)3.3.5 CRGO的FT-IR,Raman,XPS,EDX分析 (20)3.3.6 CRGO的形貌表征分析 (22)3.4本章小结 (22)第4章石墨烯/氧化锌复合材料光催化剂的制备及光催化性能的研究 (23)4.1氮掺杂氧化锌/石墨烯的制备 (23)4.1.1 N-ZnO的制备 (23)4.1.2 NZ-G的制备 (23)4.2 NZ-G复合材料的表征分析 (24)4.2.1 XRD分析 (24)4.2.2 FT-IR分析 (25)4.2.3 SEM分析 (25)4.2.4 TEM分析 (26)4.2.5 XPS分析 (27)4.2.6 UV-vis分析 (29)4.3 NZ-G光催化降解亚甲基蓝活性评价 (30)4.3.1 不同的掺氮量对N-ZnO光催化活性的影响 (30)4.3.2 不同的GO加入量对NZ-G光催化活性的影响 (31)4.3.3 不同水热温度对NZ-G光催化活性的影响 (32)4.3.4 亚甲基蓝初始浓度对光催化性能的影响 (32)4.4本章小结 (33)第5章结论与建议 (34)5.1结论 (34)5.2研究展望 (34)参考文献 (35)作者简介及攻读硕士期间所取得的科研成果 (43)致谢 (44)第1章绪论1.1石墨烯的结构与性质1.1.1结构特征石墨烯是严格意义上的二维晶体结构,是由碳原子以蜂窝状六元环密堆积形式周期性排列在二维平面上形成的,如图1.1。