First Examples of Hybrids Based on Graphene and a Ring-Shaped Macrocyclic Polyoxometalate: Synthesis, Characterization, and Properties


  • Dedicated to Professor Michael T. Pope on the occasion of 80th birthday


This work introduces facile synthetic methods of two new classes of green materials based on graphene (G) and the macrocyclic polyoxometalate [H7P8W48O184]33– (P8W48) alone or assembled with an imidazolium-based poly(ionic liquid) (PIL). The polyoxometalate serves as both an efficient graphite oxide reductant and a stabilizer. Owing to the strong adsorption of P8W48 on the resulting G sheets, water-dispersible P8W48@G hybrids were obtained without the need for surfactant or polymeric stabilizers. The P8W48@G hybrids were characterized by X-ray photoelectron spectroscopy, Raman spectroscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, and cyclic voltammetry. The presence of G in these hybrids induces an outstanding enhancement in the electrochemical properties of P8W48 in comparison with those observed with glassy carbon. Moreover, P8W48@G- and P8W48@PIL-G-based electrodes exhibit remarkable stability during prolonged potential cycling in various aqueous electrolytes. To the best of our knowledge, these are the first examples of successful syntheses of a high nuclearity polyoxometalate and graphene assemblies that might facilitate photoelectrocatalysis of multielectronic reactions.