氯化铵低温热处理制备空心碳纳米笼及其机理研究

Fabrication of Hollow Carbon Nanocages by NH_4 Cl-assisted Low-temperature Heat Treatment and Its Mechanism

碳纳米笼(CNC)的应用很广泛,但原始CNC具有金属核心,必须去除该核心才能得到空心CNC。采用氯化铵低温热处理原始CNC,再用水过滤得到空心产品。结果表明,这是一种很好的纯化方法。同时深入研究了该方法的机理,提出一种解释:氯化铵分解产物扩散进CNC后与金属核心反应,产物以气态形式扩散出CNC,最终消耗掉金属核心。

Carbon nanocages （CNCs） with a graphitic shell and hollow interior are found to have wide applications in many fields. Current raw CNCs made from most methods contain metal cores （usually, transition metals）. They need to be removed to obtain hollow CNCs. An effective method for removing the metal cores was reported. This was done by tow-temperature heat treatment in the presence of NH4 C1, followed by filtration in water. Based on the experimental results, a mechanism for the purification process is proposed. That is, the gas phase of HC1 from the decomposition of NH4 CI diffuses into CNCs and reacts with the metal cores. The resultant FeC12 then diffuses out of the CNCs. This process repeats, leading to the gradual removal of the metal cores and formation of hollow CNCs.