【作者】 程磊；

【导师】 张翔； 张加涛；

【作者基本信息】 郑州大学 ， 化学工程， 2016， 硕士

【摘要】 本文以氧化石墨烯为载体,以半导体为催化剂,通过异位复合和一步法合成的方法分别制备出石墨烯基半导体复合材料rGO-Au-CdS和rGO-Cu₂S。并分别对其在传感和光热方面的性能进行探讨。本文的研究内容及成果如下:1.本文合成了三元协同复合半导体/金属/石墨烯（Au-CdS-rGO）纳米结构。合成的Au-CdS核壳纳米颗粒中Au核大概为50 nm,Au-CdS以三明治的结构包裹在rGO中。其中GO首先被半胱氨酸盐酸盐（cys）改性处理,因为cys上的-SH能够与Au-CdS上的金属键形成较大结合力的金属S键,从而有助于纳米颗粒的分散。同时,显示负电性的GO-cys可以与正电性的十六烷基三甲基溴化铵包裹的Au-CdS进行静电吸引,二者可以紧密的结合在一起。合成的三元协同复合结构在TEM、UV-Vis、XRD表征手段下展现了一种全新的异质结构。从光电转换效率（IPCE）实验可以看出制备的三元协同复合材料能更有效的利用可见光,其在310 nm的转换效率可以达到78%,随之减小,但其在长波长的光电转换效率高于5%。荧光（PL）表征对比说明复合结构对CdS壳有淬灭作用,同时表明光生电子空穴能够在异质结构界面有效传递。拉曼和阻抗显示电子在复合结构的传递是从Au-CdS到rGO而且阻抗较小。最后我们探讨了三元协同复合半导体/金属/石墨烯纳米结构在传感（以H2O2为探测分子）方向的潜在应用。实验发现,三元协同复合半导体纳米结构修饰电极对H2O2的检测限为0.005mM,检测线性范围为0.03-7 mM。以上得知制备的三元协同复合半导体金属石墨烯纳米结构在生物传感方向有潜在的应用。2.本文利用一步法在无表面活性剂存在的情况下制备了不同复合物。通过表征,我们选择以硝酸铜作为前驱体,以与GO 5:1的比例加料,制备出具有高结晶性、窄尺寸分布和分散性好的复合材料。通过XRD和TEM对复合结构组成进行表征发现,制备的复合物为Cu₂O-rGO。然后再原位对制备的复合材料硫化,从TEM和XRD表征图可以看出,硫化后的复合材料成分是Cu₂S-rGO。然后我们对制备的复合材料进行光热性能的探讨,光热效率计算发现Cu₂O-rGO、Cu₂S和Cu₂S-rGO的光热转换效率分别为26.4%、17.2%和30.6%,说明Cu₂S-rGO不仅可以利用rGO的灰度吸收更多的光,而且可以作为载体有效的分散纳米颗粒;同时,Cu₂S自身的吸收光可以产生很重要的局域表面等离子体效应,从而增加了光热性能。更多还原

【Abstract】 In this paper, the graphene based semiconductor composites were prepared by graphene oxide and semiconductor throught the ex intu and one pot methods. Then the properties of composites were researched. The main contents and results of the present study are as follows:1. This paper demonstrated the synthesis of ternary cooperative semiconductor-metal-graphene（Au-CdS-rGO） hetero-nanostructures. The Au-CdS core-shell nanoparticles（⁵0 nm） were sandwiched between reduced graphene nanosheets. Decorating GO with L-cysteine hydrochloride plays an important role in sustaining the highly dispersion of the Au-CdS nanoparticles（NPs）. The successful modification would introduce lots of –SH function groups on the GO-cys nanosheets,which could attract the Au-CdS NPs by formation of metal-S bonding. As-fabricated photoanode exhibited higher photocurrent density compared to single-/binary-component, which could attributed to the synergistic effect of ternary cooperative Au-CdS-rGO hetero-nanostructures. First, the hetero-nanostructure could facilite more efficient utilization of incident light, which confirmed by high incident-photon-to-current-conversion efficiency（IPCE）. The excited state electron transfer is responsible for the quenching of CdS emission. The results provide further evidence that the photogenerated electrons efficiently transfer from CdS onto Au and graphene sheet. The G Raman bands indicates the photogenerated electrons could efficiently transfer from CdS onto Au and grpahene sheets, which benefits from the LSPR-induced charge separation at the interface of Au and CdS, and the electron-accepting alibity of graphene. The obtained Au-CdS-rGO photoanode was used to quantify H2O2 concentration and the detection limit was 0.005 mmol L-1,which exhibited promising application in the photoelectrochemical sensor.2. The Cu₂O-rGO was synthesized by one pot method without any surfactant,and then experiments were performed with different Cu precursor and different weight ratio between Cu precursor and GO. Different morphologies composites were fabricated. Good crystal, narrow size distribution and good dispersion compositeswas fabricated by Cu（NO3）2 precursor and 5:1 Cu precursor : GO. XRD and TEM characterizations proved the fabricated composite was Cu₂O-rGO. And then the fabricated composite was transferred by Na2 S. TEM and XRD figures said the transferred composite was Cu₂S-rGO. Photo-thermal experiments were conducted for the fabricated composite. The value of photo-thermal conversion efficiency were26.4% 、 17.2% and 30.6% for Cu₂O-rGO 、 Cu₂ S and Cu₂S-rGO respectively. In conclusion, firstly, more light could be absorbed by GO compositing with Cu₂ S and GO was used as support for dispersing Cu₂ S. Secondly, Cu₂ S could absorb light in near-infrared which could enhance the photo-thermal conversion efficiency.更多还原