Bi2O3-incorporated carbon-supported bismuth-silver (Bi@Ag/C) nanoparticle as an efficient and stable electrocatalyst for glucose electro-oxidation

In this investigation, Bi2O3-incorporated carbon-supported bismuth-silver (Bi@Ag/C) nanoparticles are synthesized using NaBH4 as reducing agent. X-ray diffraction (XRD) spectroscopy is employed to confirm the crystalline phase of our prepared electrocatalyst. The X-ray photoelectron spectroscopy (XPS) and the energy-dispersive X-ray spectroscopy (EDX) established the presence of bismuth (Bi), silver (Ag), and carbon in the synthesized bimetallic catalyst. The morphology of the as-prepared nanoparticles is observed spherical in shape using field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM and HRTEM). The electrocatalytic performance is tested by studying cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) measurement. The cyclic voltammetry study exhibits prominent oxidation peak of glucose in alkaline medium. The current value for glucose electro-oxidation is better for Bi@Ag/C (80 wt% carbon loading) than that value of bismuth oxide–induced Bi/C (80 wt% carbon loading). The better electrocatalytic activity of Bi@Ag/C electrocatalyst is observed from the cooperative effect of metallic bismuth and bismuth oxide and also the synergistic effect for the presence of silver plays an important role for the enhanced electrocatalytic performance. From EIS study, we observed a comparatively smaller charge transfer resistance of Bi@Ag/C than that of Bi/C in same test solution. Both CV and EIS profile confirm the better electrocatalytic performance of Bi@Ag/C due to the synergistic effect of bimetal. After mixing of 1 mM glucose in 0.1 M NaOH solution, the oxidation peak currents are found to be increased by 29% and 39% than that of the current in absence of glucose for Bi/C and Bi@Ag/C electrocatalysts, respectively. The stability of the Bi@Ag/C and Bi/C electrocatalysts is examined by chronoamperometry study. In chronoamperometry test, Bi@Ag/C shows much better current density than Bi/C. The energy retention of Bi@Ag/C after 500 cycles of cyclic voltammetry is tested. The effect of scan rate, temperature, and glucose concentration are also investigated in this work.