Fabrication of phosphonate functionalized platinum nanoclusters and their application in hydrogen peroxide sensing in the presence of oxygen

The water-soluble phosphonate functionalized spherical platinum nanoclusters (Pt-NCs) composed of primary nanoparticles are synthesized by the thermal decomposition of platinum(IV)-complex. The size, morphology and structure of Pt-NCs are analyzed by dynamic light scattering (DLS) and transmission electron microscopy (TEM). Attachment of phosphonate groups on Pt surface is confirmed by Fourier transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and zeta potential analysis. The phosphonate functionalized Pt-NCs efficiently suppress the oxygen reduction reaction (ORR) while fully preserving the Pt-like activity for the hydrogen peroxid reduction reaction. Importantly, at certain cathodic potential, only reduction reaction of hydrogen peroxide occurs at the Pt-NCs surface. Consequently, the phosphonate functionalized Pt-NCs can be used to fabricate a new kind of hydrogen peroxide electrochemical sensor with high performance in the presence of oxygen. Under optimized experimental conditions, the hydrogen peroxide electrochemical sensor shows fast response (less than 2 s) and wide linear range (1.0 × 10−6–1.0 × 10−3 M) in the presence of oxygen. The results presented here indicate an important new direction in the quest to design selective catalysts for the fabrication of noble-metal based H2O2 electrochemical sensor.

► The phosphonate functionalized Pt nanoclusters are synthesized by the thermal decomposition.
► The Pt nanoclusters suppress the O2 reduction reaction but faciliate H2O2 reduction reaction.
► The fabricated modified electrode shows good selectivity for H2O2 detection in the presence of O2.