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

本文研究了功率超声在室温下碳及碳相关纳米材料的化学合成中的应用。(1)超声作用于邻二氯苯(o-DCB)和其他苯衍生物导致液体变黑，这是由于苯环的聚合所致。经1h长时间辐照后，可形成黑色沉淀物，经透射电子显微镜观察为圆形的纳米石墨颗粒。(2)超声作用于苯衍生物还导致苯环断裂，甲基和亚甲基的形成，红外光谱证实了这一点。(3)金属和无机盐等固体粒子的加入大大促进了聚合或纳米颗粒的形成。当金属颗粒Co和Ni共加入时，可得到颗粒状和针状颗粒。透射电子显微镜分析表明，针状颗粒是固体、无定形的，当电子束聚焦时间较长时，可能会变形。硝酸锌的加入诱导了实心针的形成，而硝酸锌和金属锌的共同加入则导致了o-DCB超声作用产生的中空针。在单独添加金属锌的情况下，出人意料地产生了六角形的氧化锌铭牌。各种参考实验证明，空气中的氧气溶解在邻二氯苯中，然后与金属锌反应。研究还发现，适度的超声比过度的超声更有利于晶体的生长。

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.