State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, PR China.
J Am Chem Soc. 2011 Oct 5;133(39):15304-7. doi: 10.1021/ja206333w. Epub 2011 Sep 12.
On the basis of benzoxazine chemistry, we have established a new way to synthesize highly uniform carbon nanospheres with precisely tailored sizes and high monodispersity. Using monomers including resorcinol, formaldehyde, and 1,6-diaminohexane, and in the presence of Pluronic F127 surfactant, polymer nanospheres are first synthesized under precisely programmed reaction temperatures. Subsequently, they are pseudomorphically and uniformly converted to carbon nanospheres in high yield, due to the excellent thermal stability of such polybenzoxazine-based polymers. The correlation between the initial reaction temperature (IRT) and the nanosphere size fits well with the quadratic function model, which can in turn predict the nanosphere size at a set IRT. The nanosphere sizes can easily go down to 200 nm while retaining excellent monodispersity, i.e., polydispersity <5%. The particle size uniformity is evidenced by the formation of large areas of periodic assembly structure. NMR, FT-IR, and elemental analyses prove the formation of a polybenzoxazine framework. As a demonstration of their versatility, nanocatalysts composed of highly dispersed Pd nanoparticles in the carbon nanospheres are fabricated, which show high conversion and selectivity, great reusability, and regeneration ability, as evidenced in a selective oxidation of benzyl alcohol to benzaldehyde under moderate conditions.
基于苯并恶嗪化学，我们建立了一种新的方法，可合成具有精确尺寸和高单分散性的高度均匀的碳纳米球。使用包括间苯二酚、甲醛和 1,6-二氨基己烷在内的单体，并在 Pluronic F127 表面活性剂的存在下，首先在精确编程的反应温度下合成聚合物纳米球。随后，由于这种基于聚苯并恶嗪的聚合物具有优异的热稳定性，它们可以伪晶形且均匀地转化为碳纳米球，产率很高。初始反应温度 (IRT) 与纳米球尺寸之间的相关性与二次函数模型非常吻合，该模型反过来又可以预测在设定的 IRT 下的纳米球尺寸。纳米球的尺寸可以轻松降至 200nm，同时保持出色的单分散性，即分散度 <5%。大面积周期性组装结构的形成证明了颗粒尺寸的均匀性。NMR、FT-IR 和元素分析证明了聚苯并恶嗪骨架的形成。作为多功能性的证明，在碳纳米球中制备了由高度分散的 Pd 纳米颗粒组成的纳米催化剂，在温和条件下对苄醇进行选择性氧化的实验证明了它们具有高转化率和选择性、良好的可重复使用性和再生能力。
