石墨烯量子点—金属氧化物复合材料的气敏性能研究

发布时间：2018-03-04 23:37

  本文选题：石墨烯量子点　切入点：铁酸锌　出处：《安徽工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：石墨烯量子点(GQDs)是尺寸小于20 nm的石墨烯片,由于量子局域限制和边界效应而表现出很多优异的物理、化学性能。目前已被应用于例如荧光探针、光催化、电化学检测、生物成像、药物运输和传感器等领域中。本文围绕GQDs展开,详述了近年来常用的GQDs制备方法及其生成机理,之后以一水合柠檬酸为原料,合成了GQDs,再通过水热法将GQDs掺杂进金属氧化物中,制备出了GQDs-金属氧化物复合材料,着重研究了GQDs-金属氧化物复合材料的气敏性能。通过水热法制备了含有不同GQDs比重的GQDs-ZnFe_2O_4复合气敏材料,首先通过扫描电镜(SEM)、透射电镜(TEM)以及高分辨投射电镜(HRTEM)观察了复合材料的形貌特征,然后通过X射线衍射(XRD)、热重分析(TG-DSC)、红外光谱(FT-IR)、拉曼光谱(Raman)、X射线光电子能谱(XPS)、氮吸附以及孔径分布等表征手段将掺杂GQDs前后的气敏材料进行比较,证明GQDs的确已复合进金属氧化物材料中。一系列气敏测试结果证实了GQDs的加入在降低最佳工作温度的同时也增大了其对某种或多种气体的灵敏度。GQDs-ZnFe_2O_4(S-15)复合气敏材料在室温下对1000 ppm丙酮的最大灵敏度为13.31,且响应恢复时间较短,可检测到丙酮的最低浓度为5 ppm;通过水热法制备了ZnO和GQDs-ZnO复合气敏材料,首先对这些材料进行与GQDs-ZnFe_2O_4复合气敏材料相同的表征测试,再将这些复合材料与纯ZnO进行气敏测试。实验结果表明GQDs-ZnO(S-10)复合气敏材料在室温下对1000ppm乙酸气体的最大灵敏度为642,是纯ZnO最大灵敏度的72.1倍,室温下可以检测到的乙酸最低浓度为1 ppm。通过水热法制备了MoO_3和GQDs-MoO_3复合气敏材料,在进行表征测试之后再进行气敏测试。实验结果表明GQDs-MoO_3(S-6)复合气敏材料对三甲胺气体的气敏性最好,选择性变高的同时灵敏度也有了非常大的提升。在最佳工作温度230℃时,对1000 ppm三甲胺的最大灵敏度为74.08,是相同工作温度下,纯MoO_3对三甲胺灵敏度的13.9倍,可以检测到的三甲胺最低浓度为1 ppm。
[Abstract]:Graphene Quantum Dots (GQDs) are graphene wafers with size less than 20 nm, which exhibit many excellent physical and chemical properties due to quantum localization and boundary effects. In the fields of biologic imaging, drug transportation and sensor, this paper focuses on GQDs, describes the preparation methods and formation mechanism of GQDs in recent years, and then uses citric acid monohydrate as raw material. GQDs- metal oxide composites were prepared by hydrothermal doping of GQDs into metal oxides. The gas sensing properties of GQDs- metal oxide composites were studied. GQDs-ZnFe_2O_4 composite gas sensing materials with different GQDs specific gravity were prepared by hydrothermal method. The morphology of the composite was observed by SEM, TEM (TEM) and HRTEM (high resolution projection electron microscope). Then the gas sensing materials before and after doping GQDs were compared by means of X-ray diffraction (XRD), thermogravimetric analysis (TG-DSCN), FT-IR, Raman spectroscopy (Raman spectrum), X-ray photoelectron spectroscopy (XPS), nitrogen adsorption and pore size distribution. It is proved that GQDs has indeed been compacted into metal oxide materials. A series of gas sensing tests have proved that the addition of GQDs not only reduces the optimum operating temperature but also increases its sensitivity to some gas or gases. GQDs-ZnFe2O4S-15) composite gas sensing material. The maximum sensitivity to 1000 ppm acetone at room temperature is 13.31, and the response recovery time is short. The lowest concentration of acetone can be detected to be 5 ppm. ZnO and GQDs-ZnO composite gas sensing materials were prepared by hydrothermal method. The results show that the maximum sensitivity of GQDs-ZnOS-10 / GQDs-ZnOS-10 / GQDs-ZnOS-10 / GQDs-ZnOS-10 / GQDs-ZnOS-10 / GQDs-ZnOS-10 composite is 642 to 1000ppm acetic acid at room temperature, which is 72.1 times higher than that of pure ZnO. The lowest concentration of acetic acid detected at room temperature is 1 ppm. MoO_3 and GQDs-MoO_3 composite gas sensing materials were prepared by hydrothermal method. The results show that the GQDs-MoO3S-6 composite gas sensing material has the best gas sensitivity to trimethylamine gas, and the sensitivity is also greatly improved when the selectivity is higher. At 230 鈩，

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