Synthesis of silica and carbon-based nanomaterials from rice husk ash by ambient fiery and furnace sweltering using a chemical method

Abstract

Silica nanoparticles (n-SiO2), graphene nanosheets (n-Gr) and graphene oxide nanosheets (n-GO) were synthesized from the cost-effective biomass rice husk ash (RHA) by the simple chemical process. The crystallite size and micro-strain of all samples were calculated from XRD-peak profile analysis to be 1.5 - 5.4 nm and 8.11 - 28.64 MPa, respectively. FE-SEM images confirmed SiO2 nanoparticles with clustered spherical shapes and petals form of n-Gr and n-GO named RHA-1, RHA-2, RHA-3, respectively. The symmetric stretching band vibrations Si-O and O-Si-O were detected at 472, and 620 cm−1 in the FTIR spectrum, which confirmed the presence of n-SiO2. Bands at 1067, 1106, 1624 cm−1 are related to C-O stretching vibration, anhydrides C-O stretching and C=C stretching vibration of n-Gr, and n-GO, respectively. The core-level of XPS of C showed the binding energy of C‒C (283.21 eV), (291.11 eV), and O‒C=O (294.11 eV), which augmented the formation of graphene. The ratio of Raman peaks (ID/IG <1) is further confirmed the formation n-Gr of graphitic structure of sp2 carbon.