Effect of heat treatment on carbon supported PtAu based bimetallic nanomaterials for improved glucose sensitivity and electrocatalytic performance

Carbon supported PtAu based bimetallic nanomaterials were synthesized, heat treated (450°C, 2 hrs) and characterized using thermo-gravimetric analysis (TGA/DTG), scanning electron microscopy (SEM), energy-dispersive X-ray spectrometry (EDX) and X-ray diffraction (XRD). Cyclic voltammetry was employed in order to confirm the typical metallic electrochemical response of the materials and hydrodynamic amperometry was employed for direct glucose determination. The optimized nanocomposite material (Pt1Au3/C) exhibited excellent sensitivity response (27.0 μAmM^-1cm^-2, LoD 2.9 μM) toward glucose sensing, over the range 0-10 mM glucose at E _app = 0.35 V vs Ag/AgCl under neutral conditions (pH 7.4). The sensitivity (μAmM^-1cm^-2 per μg of Pt) for heat treated Pt1Au3/C is 3.46 times that observed for untreated Pt1Au3/C and 4.36 times that shown by heat treated Pt1Au1/C. All these results clearly demonstrated the effect of heat-treatment and the role of Au in improving catalytic activity and in effective Pt surface utilization, collectively resulting in excellent response toward glucose electro-oxidation. Overall, thematerials demonstrated sensitive and reproducible responses, while eliminating the pH, temperature and lifetime issues associated with enzyme based electrodes. These decorated nanoscale materials are capable of large scale production and are of great promise in the quantification of glucose in real clinical samples as well as can be used in food industry, fermentation/bio- process control and industrial processes.