聚合物热解法制备碳纳米管/铝复合粉末及其反应动力学研究

Preparation and Reaction Kinetics of Carbon Nanotubes/Aluminum Composite Powders Using Polymer Pyrolysis Method

采用聚合物热解化学气相沉积(PP-CVD)法,通过聚乙二醇(PEG)的原位热解提供碳源、柠檬酸(CA)和硝酸钴反应产生催化剂纳米粒子,在微纳米级的片状铝粉基底上原位生长碳纳米管(CNTs)。通过实验和反应动力学建模研究了PP-CVD反应机理,揭示了PEG热解气相成分和催化剂纳米粒子表面气-固反应对CNTs生长速率的影响规律。CO初始分压和反应温度提高,CNTs生长速率提高;H2初始分压和催化剂密度提高,CNTs生长速率降低。模型预测的CNTs平均长度随反应温度和反应时间的变化趋势符合实验结果。因此,本研究为进一步优化CNTs/铝复合粉末制备工艺提供了新的理论依据。

The method of polymer pyrolysis chemical vapor deposition （PP-CVD） was used to m sttu grow cartoon nanotubes （CNTs） on the micro and nano sized flake like aluminum powder substrates. The vapor species were in situ produced by pyrolysis of polyethylene glycol （PEG） including the carbon sources, which was the main difference between the PP-CVD and conventional CVD methods, while the catalyst nanoparticles were pro- duced by the reaction between citric acid （CA） and cobalt nitrate （C0（NO3）2） on aluminum powder surfaces. The reaction mechanism of PP-CVD was studied with the analysis of experiments and reaction kinetics mod- eling, revealing the influence of the vapor species produced by pyrolysis of PEG and CA and surface vapor-solid re- actions on catalyst nanoparticles on CNT growth rates. The CNTs growth rates increases with the increase of reaction temperature and initial partial pressure of CO, which is influenced by the content of PEG and CA, and decreases with the increase of catalyst density and initial partial pressure of H2. The variation trends of the simulated CNTs average length with reaction temperature and time are consistent with the experimental results Thus, this work provides new theoretical basis to the further optimization of fabricating CNTs/aluminum composite powders.