Fr Francium

Two-dimensional carbon nanostructures, including carbon nanoflakes that are formed from the disassembly of carbon foams and carbon–metal composites, were directly synthesized using the stem pith of the rice-paper plant (SPRP) as the carbon precursor and also the synthesis template. SPRP has a foamlike porous structure. SPRP was pyrolyzed to prepare carbon foam with ultralow apparent density, and this foam was ruptured to produce carbon nanoflakes with a lateral size up to hundreds of micrometers and a thickness of approximately 100 nm. Palladium and platinum were added to the SPRP foams by wet impregnation, and the impregnated foams were subsequently converted into composites of metal nanoparticles and carbon in the form of foams or nanoflakes. The composites were characterized using electron microscopy, energy-dispersive spectroscopy, X-ray diffraction, and Raman spectroscopy. The metal nanoparticles were found to be highly crystalline with diameters in the range of several tens of nanometers (palladium) and several nanometers (platinum), and were uniformly distributed throughout the carbon nanoflakes. The amount of metal in the composite was tunable by changing the impregnation time and the concentration of the impregnation solution.Two-dimensional, flake-shaped carbon and carbon–metal nanocomposites with nanometer-sized thickness and a large lateral size up to hundreds of micrometers were easily synthesized using a naturally existing cellular material, the stem pith of the rice-paper plant, both as the carbon precursor and also the synthesis template.