▎ 摘　　要

A simple method was developed to construct graphene-nanosilica composites. Polyethyleneimine (PEI), which is a synthetic polyamine functionally analogous to bio-polyamines in organisms, was used as a template/scaffold/catalyst to direct nanostructured silica formation, i.e., PEI hybridised silica (PEI@SiO2). Due to the cationic nature and reducibility of PEI, the hybrid PEI@SiO2 surface instantly adsorbs the negatively charged graphene oxide (GO) at room temperature, leading to PEI@SiO2@GO composites. The GO was further reduced in situ into reduced grapheme oxide (rGO) to form PEI@SiO2@rGO at 90 degrees C. The PEI@SiO2@GO showed a high removal efficiency of 96% for Hg2+ from a 10 ppm solution; PEI@SiO2@rGO could decolorise organic dyes (rhodamine B or methyl blue) from solution after 30 min. Unlike previously published methods for producing graphene-inorganic composites, this method is general to other polyamine-silica (or metal oxide) systems and has the synergistic efficiency to target GO without additional surface modification and reductants.