Carbon nanocubes and nanobricks from pyrolysis of rice.

Carbon nanocubes and nanobricks were synthesized by pyrolyzing rice powder at 600 degrees C under nitrogen atmosphere. Purification with concentrated nitric acid introduced approximately 0.1 mol/g of carboxylic acid groups as found by acid-base titrimetric analysis. XRD pattern showed the 0.15 mol/g basic graphitic structure of these nano carbon materials. Their SEM and TEM images revealed cube or brick shaped nano crystals. These nanocrystals are further characterized by FT-IR, Raman, and EDAX analysis. High density wrapping of carboxylated acid groups introduces surface passivation of these nano carbon cubes and nano carbon bricks exhibiting photoluminescence. Solid state electronic spectrum showed several bands in the ultraviolet and visible region and excitation at 336 and 474 nm generates photoluminescence respectively in the ultraviolet and visible region.