A novel strategy for preventing aggregation, increasing surface area, and maintaining catalytic activity of water-soluble graphene nanosheet (GNS) catalysts is introduced, and use of the synthesized nanocatalyst [GNS (matrix)/metal (catalyst)/metal oxide (spacer)/ceramic (protector)] as recyclable nanocatalysts without loss of performance is demonstrated. Our graphene nanocomposite (GNC) armed with nanoneedles is fabricated by the synthesis of Au on GNS, followed by stepwise synthesis of needle-like IO and SiO2, in order. The distinctive structures of the needle-like layers prevent aggregation and contamination of the GNS catalysts, and allow recycling, both of which enhanced catalytic ability. The research demonstrates the possibility of a safe coating for water-soluble GNS catalysts, which are reactive to ionic species, and their application as nanocatalysts for the chemo-selective transformation of toxic substances. Our sandwich-like GNCs for recyclable nanocatalysts provide a new design concept for reusable GNS catalysts.
