Carbon Nanomaterial-Phosphomolybdate Composites for Oxidative Electrocatalysis

Novel hybrid nanocomposites based on the immobilisation of tetrabutylammonium salts of phosphomolybdates (PMo12, PMo11, PMo11V, and PMo10V2) on single-walled carbon nanotubes or graphene flakes were prepared. Glassy carbon electrodes modified with carbon nanocomposites produce cyclic voltammograms that are consistent with surface-confined redox processes attributed to Mo-centred reduction (Mo-VI -> Mo-V) and vanadium reduction (V-V -> V-IV) for PMo11V and PMo10V2. Furthermore, they show very high stabilities and well-resolved redox peaks with high current intensities. The observed enhancement of the electrochemical properties of polyoxometalates (POMs) is a consequence of strong electronic communication between POMs and carbon nanomaterials. Nanocomposites of vanadium-phosphomolybdates exhibit superior V-based electrocatalytic properties towards ascorbic acid oxidation in comparison with free POMs; moreover, PMo11V@graphene shows an outstanding sensing performance for the detection of dopamine.