High-quality graphene quantum dots from agricultural waste

Rice husks – the outer, protective covering of rice kernels, which makes up more than 20 wt% of the entire kernel – are the by-product of rice milling. Given the sheer volume of this agricultural waste, roughly 120 million tons a year, researchers have been exploring ways to utilize this silica-rich biomass for the synthesis of valuable materials.

In previous Nanowerk Spotlights we already have reported on two successful strategies by nanotechnology researchers to recycle rice husks to synthesize graphene and to produce nanoporous silicon for high-capacity lithium battery anodes.

"Due to the high concentration of silica in rice husks, most of the present research focuses on the preparation of silicon-based materials, which exhibit broad applications in the fields of adsorption, catalysis, energy storage, etc.," Dr. Luyi Sun, an Associate Professor in the Institute of Materials Science at the University of Connecticut, explains to Nanowerk. "It is worth pointing out that there is also a large amount of organic components (ca. 72-85 wt%) in rice husks, which is typically wasted in the preparation of these silica materials."