Synergistic Hybrid Catalyst for Ethanol Detection: Enhanced Performance of Platinum Palladium Bimetallic Nanoparticles Decorated Graphene on Glassy Carbon Electrode

Abstract

The present study highlights the first time use of hybrid synergy electrocatalysis to design a cost effective, non-enzymatic ethanol sensor. The nanohybrid has been synthesized by decorating platinum palladium bimetallic nanoparticles (Pt‒PdNPs) on graphene nanosheets (G/Pt‒PdNPs). Field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, electrochemical measurements and UV-Vis spectrophotometry have been used to characterize the nanocomposite. An ethanol oxidation current of 332 μA was obtained with the use of G/Pt‒PdNPs modified glassy carbon electrode (GCE) that is 167 times higher than that of bare GCE in cyclic voltammetry studies with a potential scan rate of 50 mV/s in 0.1 M NaOH as the supporting electrolyte. Chronoamperometry studies have shown a distinct increase in the current for increasing concentration of ethanol with a wide range of linearity extending from 5 mM to 3 M and a detection limit of 1 mM with the use of G/Pt‒PdNPs. Quantum mechanical modeling using density functional theory was used to arrive at the minimization energies of G/Pd, G/Pt and G/Pt‒Pd in the presence and absence of ethanol. The improved catalytic activity of G/Pt‒PdNPs nanocomposite for ethanol detection is on account of the cooperative effects of Pt and PdNPs, coupled with the high conducting nature of graphene.