Glucose oxidation reaction at palladium-carbon nano-onions in alkaline media

Abstract

The glucose oxidation reaction, at Pd on unsupported carbon nano-onions (Pd/CNOs), has been studied by using physical and electrochemical characterization techniques. The rotating disk slurry electrode (RoDSE) technique was used for the Pd electrodeposition at the carbon support. The Pd/CNO catalyst was compared with the optimized RoDSE-prepared Pd/Vulcan XC-72R nanoflake catalyst for the glucose oxidation reaction by using different physical and electrochemical characterization techniques. Powder XRD analysis verified the effect of the carbon support material on the Pd crystallinity and size nanoparticles. Raman spectroscopy and X-ray photoelectron spectroscopy were used to understand the chemical structure of each carbon support before and after the Pd electrodeposition. The surface area and porosity of both Pd/C catalysts and their respective carbon substrates were investigated using N2 adsorption analysis. Transmission electron microscopy images established the morphology and the sizes of the Pd/CNOs, obtaining a large dispersion of nanoparticles with an average diameter size between 35 and 40 nm, with smaller particles in the range between 2 and 10 nm. Finally, cyclic voltammetry (CV) and linear sweep voltammetry (LSV) were used to compare the electrocatalytic activity of Pd/C, Vulcan XC-72R, and CNOs, for the glucose oxidation reaction in alkaline media. The results indicate that Pd/CNOs has the capacity to oxidize glucose in the normal glucose range between 5 and 8 mM, the normal range of glucose in human blood.