Hybrid materials of platinum nanoparticles and thiol-functionalized graphene derivatives

Hybrid materials of platinum nanoparticles (Pt-NP) and thiol-functionalized thermally reduced graphite oxide (TRGO-SH), were synthesized by thermal decomposition of the organometallic precursor methylcyclopentadienyl-trimethylplatinum(IV) in dispersions of TRGO-SH in the ionic liquid 1-n-butyl-3-methyl-imidazolium tetrafluoroborate under microwave-assisted heating conditions. For the kinetic stabilization of Pt-NPs on TRGO-SH no additional donor ligands were necessary. The ionic liquid acts as separator of the TRGO-SH graphene sheets and as kinetic stabilizing template in the Pt-nanoparticle formation process. Thiol-functionalization of thermally reduced graphite oxide was carried out using three different synthetic procedures: (1) ring opening of propylene sulfide; (2) xanthate grafting and reduction to thiol; (3) reduction, thioesterfication under Mitsunobu conditions and ester hydrolysis. These three different TRGO-SH materials (1), (2) and (3) had different sulfur contents (1.2, 2.5 and 14 wt.%, respectively) and were used as support materials for platinum nanoparticles. The loading of Pt-NPs on TRGO-SH (1), (2) and (3) was 3.2, 3.5 and 8.8 wt.% with particle diameters determined from transmission electron microscopy of (9 ± 4), (2.5 ± 0.9) and (5 ± 2) nm, respectively.