High entropy alloy nanoparticle - graphene (HEA:G) composite for non-enzymatic glucose oxidation : optimization for enhanced catalytic performance

Abstract

High entropy alloy (HEA) metal nanoparticles engineered graphene composites (HEA:G) were produced via green approach involving mechanical milling and sonication assisted exfoliation. Mixture of metal powders and graphite (metal-to-graphite weight ratio: 20%, 50%, 70%, 90%) were ball milled and exfoliated. As produced 20:80, 50:50, 70:30, 90:10 - HEA:G composites electrochemical activity was explored using the redox probe potassium ferricyanide [K3Fe(CN)6] and for the non-enzymatic detection of glucose. From cyclic voltammetry(CV) response, the significant electron transfer kinetics for K3Fe(CN)6 was found for 20:80, 50:50, 70:30 composites, whereas reduced activity was observed with 90:10. Also, 20:80, 50:50, 70:30 composites exhibited notable oxidation of glucose in 0.1 M PBS compared to 90:10. The anodic current indicating oxidation of glucose was found to be increasing linearly with HEA:G composite - 20:80<50:50<70:30. However, DPV measurements indicate better working potential from 0.45 V to 0.4 V followed by saturation in the oxidation currents for 50:50 and 70:30 composites. The sensitivity obtained for HEA:G composites 20:80, 50:50, 70:30 were 12.09 μAmM−1cm−2, 22.99 μAmM−1cm−2, 18.2 μAmM−1cm−2 respectively. Hence, 50:50 and 70:30 are the efficient composites exhibiting excellent catalytic activity indicating the prominence of HEA:Graphene composites and their synergism.

Keywords

• Electrochemistry
• High entropy alloy – graphene (HEA:G) composite
• Electro-catalysis
• Non-enzymatic electrochemical sensor
• Ball milling