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The composites consisting of nitrogen-doped carbon nanotubes (N-CNTs) and nitrogen-doped carbon nanofibers (N-CNFs) were fabricated using a mixture of nickel foam (template) and imidazole (solid precursor) in a facile one-step chemical vapor deposition (CVD) process. The morphology and microstructure of the N-doped carbon nanotubes/N-doped carbon nanofibers hierarchical composites (N-CNTs/N-CNFs) were determined by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Raman spectra, and X-ray photoelectron spectroscopy. The results indicated that the sample manifests regular hierarchical composites, great graphitization, and nitrogen doping. Furthermore, a probable growth mechanism is presented to analyze the composites. [ABSTRACT FROM AUTHOR]

Abstract: We report a direct synthesis of single-layer, bi-layer, and multi-layer graphene films on a nickel grid surface by chemical vapor decomposition of liquid precursor benzene. The direct route, by avoiding several wet chemical steps and accompanying mechanical stresses and contamination common to all presently reported graphene transfer to microscopy grid method, enables providing pristine microstructure information for as-prepared graphene films. A liquid precursor based growth route opens a new door to tailor the electronic properties of graphene by doping heteroatoms using various organic liquids containing the dopant atoms. [Copyright &y& Elsevier]

Abstract: Single- and multi-layer nitrogen-doped graphene was deposited on TEM copper grids by chemical vapor deposition from ammonia and methane. By controlling the gas mixture ratio the nitrogen atomic percentage in the host graphene can be regulated, ranging from 0.7% to 2.9%. High-resolution transmission electron microscopy and Raman spectroscopy reveal that high-quality nitrogen-doped single- and multi-layer graphene sheets were obtained. The existence of nitrogen substitution in the graphene lattices is confirmed by X-ray photoelectron spectroscopy. [Copyright &y& Elsevier]

U-shaped graphene domains have been prepared on a copper substrate by chemical vapor deposition (CVD), which can be precisely tuned for the shape of graphene domains by optimizing the growth parameters. The U-shaped graphene is characterized by using scanning electron microscopy (SEM), atomic force microscopy (AFM), transmission electron microscopy (TEM), and Raman. These show that the U-shaped graphene has a smooth edge, which is beneficial to the seamless stitching of adjacent graphene domains. We also studied the morphology evolution of graphene by varying the flow rate of hydrogen. These findings are more conducive to the study of morphology evolution, nucleation, and growth of graphene domains on the copper substrate. [ABSTRACT FROM AUTHOR]