Immobilization and electrocatalysis of Ru(III) ions on phosphonate functionalized gold nanoparticles

The surface chemical functionalization generally endows gold nanoparticles (Au-NPs) with expanding applications in sensors, medicine and catalysis because of the synergistic effect. In this work, we report a novel strategy for the synthesis of phosphonate functionalized Au-NPs (P-Au-NPs) by using vinylphosphonic acid as the reducing agent and stabilizing agent. The morphology, composition, and structure of P-Au-NPs are fully characterized by various spectroscopy techniques. The resultant P-Au-NPs show a remarkable colloidal stability, which likely arises from strong electrostatic effect of negatively charged phosphonate groups and the extremely hydrophilic property of phosphonate groups. In addition, the as-prepared P-Au-NPs effectively bind Ru^III ions via coordination interaction, which can be used to construct an iodate amperometric sensor with the wide linear range and low detection limit.