Facile synthesis of water-soluble fullerene–graphene oxide composites for electrodeposition of phosphotungstic acid-based electrocatalysts

Highlights: • C60 or C70 is supported on GO via noncovalent conjunction through facile grinding. • GO–C60/C70 composite has solubility as high as 5 mg mL−1 for months. • GO–C60/C70 can be one-step electrodeposited with phosphotungstic acid (PTA). • PTA–GO–C60/C70 film electrode show catalytic activity for the redox of biomolecules. -- Abstract: A versatile approach to the dispersion of C60/C70 in water with high concentration and stability by graphene oxide (GO) was reported here. By simply grinding with GO, C60/C70 can be readily dissolved in water with solubility up to 5 mg mL−1 and stability for more than three months. Transmission electron microscopy indicated that C60/C70 formed a uniform and high-density layer on the surface of GO, which may be achieved through the strong π–π interaction between fullerenes and GO, as supported by Fourier transform infrared spectroscopy, Raman and ultraviolet–visible spectroscopy spectra. Through a simple electrodeposition method, two novel phosphotungstic acid–graphene oxide–fullerene hybrids (i.e., PTA–GO–C60 and PTA–GO–C70) were formed on glassy carbon electrodes. The resulting hybrid modified electrodes exhibited enhanced electrocatalytic activity for the oxidation of a variety of small biomolecules, including dopamine, ascorbic acid, uric acid, L-tryptophan, tyrosine, indole-3-acetic acid, salicylic acid and 6-benzylaminopurine, reflected by the remarkably enlarged peak currents and apparently reduced oxidation overpotentials as compared with those on either PTA or PTA–GO modified electrodes