Platinum nanoparticle decoration of carbon materials with applications in non-enzymatic glucose sensing

Nanocomposites of ethylene glycol protected platinum nanoparticles were prepared in the presence of activated carbon (AC), multi-walled carbon nanotubes (MWNTs) and carbon nanofibres (CNFs) at 20% (w/w) Pt loading and their potential in non-enzymatic glucose sensing evaluated. Physical and electrochemical characterization of these hybrid materials was enabled using transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and cyclic voltammetry. The average platinum nanoparticle diameters, as determined from TEM and XRD measurements, were 2 ± 1 to 3 ± 1 nm. The electrochemically active surface area of the platinum nanoparticles were found to be 91, 78 and 128 m2 g−1 for Pt-C, Pt-MWCNT and Pt-CNF respectively, as determined by the hydrogen adsorption/desorption phenomenon, using cyclic voltammetry in H2SO4. The nanomaterials were applied to the direct non-enzymatic quantization of glucose over its physiological range in the absence of the enzyme glucose oxidase. Hydrodynamic amperometric at Eapp = 0.55 V vs. Ag/AgCl in phosphate buffer (pH 7.4) was employed and the materials responded linearly to glucose (at pH 7.4, 298 K) over the range 2–20 mM (R2 = 0.99) with sensitivity 1.07, 1.10 and 0.52 μA mM−1 cm−2 for Pt-C, Pt-MWCNT and Pt-CNF respectively.