Base Metal Catalyzed Graphitization of Cellulose: A Combined Raman Spectroscopy, Temperature-Dependent X-ray Diffraction and High-Resolution Transmission Electron Microscopy Study
Base Metal Catalyzed Graphitization of Cellulose: A Combined Raman Spectroscopy, Temperature-Dependent X-ray Diffraction and High-Resolution Transmission Electron Microscopy Study
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DOI：
10.1021/acs.jpcc.5b00477
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发表时间：
2015-05-14
影响因子：
3.7
通讯作者：
Jenneskens, Leonardus W.
中科院分区：
文献类型：
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作者：
Hoekstra, Jacco;Beale, Andrew M.;Jenneskens, Leonardus W.
均相负载铜、镍、钴或铁硝酸盐的微晶纤维素(MCC)球是确定在T=500-800℃的温度范围内形成高度分散的贱金属纳米颗粒的温度以及在T=500-800℃的温度范围内催化石墨化发生的优良模型体系。Fcc钴，T=570℃；bcc铁，T=700℃)。此外，根据拉曼光谱和TD-X射线衍射仪，在不同的温度下，镍(T>；=800℃)、钴(T>；=800℃)和铁(T>；=715℃)纳米粒子催化非晶态碳载体转化为涡轮层状石墨碳带。然而，铜被发现是不活跃的。此外，HRTEM显示，镍(500摄氏度)
Microcrystalline cellulose (MCC) spheres homogeneously loaded with the nitrate salts of copper, nickel, cobalt, or iron are excellent model systems to establish the temperature at which highly dispersed base metal nanoparticles are formed as well as to establish the temperature at which catalytic graphitization occurs during pyrolysis in the temperature regime T = 500-800 degrees C. Temperature-dependent X-ray diffraction (TD-XRD) and high-resolution transmission electron microscopy (HRTEM) showed that the base metal nanoparticles are smoothly formed from related base metal oxides via carbothermal reduction (fcc copper, T < 500 degrees C; fcc nickel, T < 500 degrees C; fcc cobalt, T = 570 degrees C; bcc iron, T = 700 degrees C). Moreover, it is shown that at distinct temperatures nickel (T >= 800 degrees C), cobalt (T >= 800 degrees C), and iron (T >= 715 degrees C) nanoparticles catalyze the conversion of the amorphous carbon support into ribbons of turbostratic graphitic carbon according to Raman spectroscopy and TD-XRD. Copper, however, was found to be inactive. Furthermore, HRTEM revealed that nickel (500 degrees C