Sonochemical Synthesis of Carbon-related Nanomaterials in Liquid at Room Temperature

本文研究了功率超声在室温左右液相化学合成碳及碳相关纳米材料中的应用。(1)对邻二氯苯（o-DCB）和其他一些苯衍生物进行超声波处理，使液体变暗，这是由于苯环聚合引起的。长时间辐照（如1 h）形成黑色沉淀，透射电镜发现其为圆形石墨纳米颗粒。(2)超声波对苯衍生物也会导致苯环断裂，甲基和亚甲基的形成，并通过红外光谱证实了这一点。(3)固体颗粒如金属和无机盐的加入大大增强了聚合或纳米颗粒的形成。当Co和Ni金属颗粒共添加时，得到颗粒状和针状颗粒。透射电镜分析表明，针状颗粒是固体的，无定形的，当电子束长时间聚焦时可能会变形。由此推断，这种颗粒是一种低质量的聚合物，就像由粘性液体形成的纱线一样。(4)硝酸锌的加入可形成实心针，而硝酸锌与金属锌的共添加可形成o-DCB超声作用下的空心针。在单独添加金属锌的情况下，意外地产生了六角形氧化锌铭牌。各种参考实验证明，空气中的氧气溶解于o-DCB中，然后与金属锌发生反应。还发现，适度超声比过度超声对晶体生长更有效。

The present study is concerned with the application of a power ultrasound to chemical syntheses of carbon and carbon- related nanomaterials in liquid phase at around room temperature.(1)Ultrasonication to o-dichlorobenzene (o-DCB) and some other benzene derivatives caused the darkening of the liquid, which is due to polymerization of benzene rings. Long irradiation such as 1 h resulted in the formation of black precipitates, which was found to be a round-shaped nanoparticle of graphite by transmission electron microscopy.(2)Ultrasonication to the benzene derivatives also induced the breakage of benzene rings and the formation of methyl and methylene group, which were confirmed by an infrared spectroscopy.(3)Addition of solid particles such as metals and inorganic salts greatly enhanced the polymerization or the formation of nanoparticles. When metallic particles of Co and Ni were co-added, granular and needle-like particles were obtained. TEM analysis revealed that the needle-like particles were solid, amorphous, and likely to deform when an electron beam was focused for a long time. It was inferred that this particles was a low weight polymer which were formed just like a yarning from a sticky liquid.(4)Addition of zinc nitrate induced the solid needles, while co-addition of zinc nitrate and metallic zinc induced the hollow needles from the ultrasonication of o-DCB. In the case of sole addition of metallic zinc, unexpectedly, hexagonal nameplates of zinc oxide were produced. A variety of referential experiments proved that oxygen in air dissolved in o-DCB and then reacted with metallic zinc. It was also found that a moderate sonication was more efficient for the crystal growth than an excessive sonication.