Onion-like fullerenes synthesized by arc discharge in water were used as support of Pt nanoparticles as electrocatalytic materials for direct methanol fuel cell. Uniform platinum nanoparticles with the average diamete...Onion-like fullerenes synthesized by arc discharge in water were used as support of Pt nanoparticles as electrocatalytic materials for direct methanol fuel cell. Uniform platinum nanoparticles with the average diameter of about 4.3 nm were well dispersed on the surface of onion-like fullerenes by impregnation-reduction method. The morphologies and microstructures of the as-prepared composites were studied by means of XRD and TEM. Electrochemical analysis shows that this kind of nano material may be an excellent candidate to be used as the support of catalyst for methanol electrochemical oxidation.展开更多
探索了纯石墨电极在水中放电制备洋葱状富勒烯(Onion-like fu llerenes,OLFs)的过程和工艺。用高分辨透射电镜(H igh reso lution transm ission electron m icroscope,HRTEM)对生成的OLFs进行了形貌、结构的观察与表征。分析结果表明...探索了纯石墨电极在水中放电制备洋葱状富勒烯(Onion-like fu llerenes,OLFs)的过程和工艺。用高分辨透射电镜(H igh reso lution transm ission electron m icroscope,HRTEM)对生成的OLFs进行了形貌、结构的观察与表征。分析结果表明制得的OLFs具有各种不同形状的内核,石墨化程度很高,直径分布在5nm^40nm范围内。在一定范围内随着电流强度的增大OLFs的产量和产率都有不同程度的提高。展开更多
The synthesis of carbon onions in the laboratory by various methods is common;however, naturally occurring carbon onions have only been found in a few geological samples on Earth. This study used high-resolution trans...The synthesis of carbon onions in the laboratory by various methods is common;however, naturally occurring carbon onions have only been found in a few geological samples on Earth. This study used high-resolution transmission electron microscopy to identify natural carbon onions in seven intrusion-affected coal samples collected from Permian coal-bearing strata in the Yongan Coalfield, Fujian Province, South China. This study identified the largest natural carbon onions ever recorded on Earth;their outer diameter was ~55 nm. Granite porphyry intrusions and quartz hydrothermal veins are abundant in the Permian coal-bearing strata in this coalfield. All samples collected were tectonically deformed coals with highly developed structural fractures, friction mirror planes, and maximum vitrinite reflectance values of 4.0–9.5%. Natural carbon onions observed in the coal samples had single or multiple cores, with 24–46 graphitic shells characterized by outer diameters of 24–55 nm. The maximum vitrinite reflectance, outer diameter, and graphitic shell number of carbon onions in the intrusion-affected coal were positively correlated, indicating that the carbon onions were secondary products formed during coal metamorphism owing to magmatic intrusion. Our results suggest that carbon onions in intrusion-affected coal are synthesized by chemical vapor deposition. We speculate that natural carbon onions exist mainly in fractures or cavities, similar to vapor-deposited pyrolytic carbon, which is the leading cause of the uneven distribution of carbon onions in intrusion-affected coals in the study area.展开更多
基金This work was financially supported by National Basic Research Program of China (No.2004CB217808), National Natural Science Foundation of China (No.20471041) Key Project of National Natural Science Foundation of China (No.90306014), Natural Science Foundation of Shanxi Province (No.20051018) and Shanxi Research Fund for Returned Scholars (No.200428,200523).
文摘Onion-like fullerenes synthesized by arc discharge in water were used as support of Pt nanoparticles as electrocatalytic materials for direct methanol fuel cell. Uniform platinum nanoparticles with the average diameter of about 4.3 nm were well dispersed on the surface of onion-like fullerenes by impregnation-reduction method. The morphologies and microstructures of the as-prepared composites were studied by means of XRD and TEM. Electrochemical analysis shows that this kind of nano material may be an excellent candidate to be used as the support of catalyst for methanol electrochemical oxidation.
文摘探索了纯石墨电极在水中放电制备洋葱状富勒烯(Onion-like fu llerenes,OLFs)的过程和工艺。用高分辨透射电镜(H igh reso lution transm ission electron m icroscope,HRTEM)对生成的OLFs进行了形貌、结构的观察与表征。分析结果表明制得的OLFs具有各种不同形状的内核,石墨化程度很高,直径分布在5nm^40nm范围内。在一定范围内随着电流强度的增大OLFs的产量和产率都有不同程度的提高。
基金financially supported by the National Natural Science Foundation of China (Grant Nos. 42130802 and 41972176)the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions。
文摘The synthesis of carbon onions in the laboratory by various methods is common;however, naturally occurring carbon onions have only been found in a few geological samples on Earth. This study used high-resolution transmission electron microscopy to identify natural carbon onions in seven intrusion-affected coal samples collected from Permian coal-bearing strata in the Yongan Coalfield, Fujian Province, South China. This study identified the largest natural carbon onions ever recorded on Earth;their outer diameter was ~55 nm. Granite porphyry intrusions and quartz hydrothermal veins are abundant in the Permian coal-bearing strata in this coalfield. All samples collected were tectonically deformed coals with highly developed structural fractures, friction mirror planes, and maximum vitrinite reflectance values of 4.0–9.5%. Natural carbon onions observed in the coal samples had single or multiple cores, with 24–46 graphitic shells characterized by outer diameters of 24–55 nm. The maximum vitrinite reflectance, outer diameter, and graphitic shell number of carbon onions in the intrusion-affected coal were positively correlated, indicating that the carbon onions were secondary products formed during coal metamorphism owing to magmatic intrusion. Our results suggest that carbon onions in intrusion-affected coal are synthesized by chemical vapor deposition. We speculate that natural carbon onions exist mainly in fractures or cavities, similar to vapor-deposited pyrolytic carbon, which is the leading cause of the uneven distribution of carbon onions in intrusion-affected coals in the study area.
