Dry mechanochemical route to nanocomposites containing multi-layer graphene

• Simple and sustainable route for preparing conductive graphene–silicate materials. • Water-free mechanochemical intercalation of glucose into montmorillonite. • Multilayer graphene with interlayer spacing of ∼0.335 nm formed by pyrolysis. • Electrical conductivity up to 36.01±8.41 S·m-1. • Mechanochemical intercalation leads to similar results as intercalation in water. The main objective of this study is to investigate the feasibility of preparing an electrically conductive nanocomposite containing graphite or graphene from glucose mechanochemically intercalated into montmorillonite (MMT). Four different ratios of glucose and MMT were dry-mixed by pestle in mortar, pressed into tablets, and pyrolyzed at 1300°C. Various analytical techniques were used to characterize both original and pyrolyzed samples. Thermogravimetric analysis and elemental analysis were used to confirm the composition of the original samples. Elemental analysis also determined the amount of carbon in pyrolyzed samples. X-ray powder diffraction (XRPD) identified phases formed during pyrolysis. Raman microscopy studied the presence of graphite, graphene, and amorphous carbon. Transmission electron microscopy provided an in-depth observation of the morphology, proving that the layers in the pyrolyzed samples matched the d002 distances associated with graphitic carbon as revealed by XRPD analysis. X-ray photoelectron spectroscopy confirmed the dominant proportion of sp2 carbon (up to 75 %) and revealed a minor proportion of carbon-oxygen bonds (< 15 %). The combined results confirmed that pyrolysis of mechanochemically intercalated MMT yields a material that is similarly conductive to that prepared by pyrolysis of MMT intercalated in water. This is an important step in the process of simplifying the preparation of electrically conductive nanocomposites containing graphite or graphene.