Silver-functionalized bismuth oxide (AgBi2O3) nanoparticles for the superior electrochemical detection of glucose, NO2- and H2O2

Abstract

In this study, silver-functionalized bismuth oxide (AgBi₂O₃) nanoparticles (SBO NPs) were successfully synthesized by a highly efficient hydrothermal method. The as-synthesized SBO nanoparticles were characterized using FT-IR, P-XRD, XPS, HR-SEM, and HR-TEM analytical methods. It was found that the NPs were in spherical shape and hexagonal crystal phase. The newly prepared SBO electrode was further utilized for the detection of glucose, NO₂^- and H₂O₂ by cyclic voltammetry (CV) and amperometric methods. The electrodes exhibited high sensitivity (2.153 μA mM^-1 cm^-2 for glucose, 22 μA mM^-1 cm^-2 for NO₂^- and 1.72 μA mM^-1 cm^-2 for H₂O₂), low LOD (0.87 μM for glucose, 2.8 μM for NO₂^- and 1.15 μM for H₂O₂) and quick response time (3 s for glucose, 2 s for both NO₂^- and H₂O₂ respectively). The sensor exhibited outstanding selectivity despite the presence of various interferences. The developed sensor exhibited good repeatability, reproducibility, and stability. In addition, the sensor was used to measure glucose, H₂O₂ in human serum, and NO₂^- in milk and river water samples, demonstrating its potential for use in the real sample.

Scheme 1. Schematic diagram for the synthesis and fabrication of the SBO–GC electrode and electrochemical applications.

Fig. 1. (a) XRD pattern of SBO NPs and (b) FT-IR spectrum of SBO NPs.

Fig. 2. XPS spectrum of SBO NPs: (a) XPS survey spectrum, (b) XPS spectrum of Ag 3d, (c) XPS spectrum of Bi 4f, and (d) XPS spectrum of O 1s.

Fig. 3. (a) and (b) HR-SEM images at lower and higher magnifications for SBO NPs, (c) EDX spectrum of SBO NPs, (d) HR-TEM image of SBO NPs (inset shows the histogram plot of particle size determination), (e) SAED pattern and (f) IFFT image of SBO NPs.

Fig. 4. (a) CV plot of bare GCE and SBO–GCE in the absence and presence of 1 mM glucose at a scan rate of 50 mV s⁻¹, (b) CV plot at different scan rates from 10 to 100 mV s⁻¹ (inset shows the linear relationship between the current and the scan rate), (c) amperometric i–t curve for the increasing concentration of glucose 1 μM to 5.847 mM, (d) calibration plot of the SBO–GCE for current vs. concentration of glucose, (e) amperometric response of the selectivity study recorded with commonly used interferences, and (f) histogram plot of real-sample analysis for glucose detection using the SBO–GCE.

Fig. 5. (a) CV plot of the bare GCE and SBO–GCE in the absence and presence of 1 mM NO₂⁻ at a scan rate of 50 mV s⁻¹, (b) CV plot at different scan rates from 10 to 100 mV s⁻¹ (inset shows the linear relationship between current vs. scan rate), (c) amperometric i–t curve for the increasing concentration of NO₂⁻ 1 μM to 5.847 mM, (d) calibration plot of the SBO–GCE for current vs. concentration of NO₂⁻, (e) amperometric plot of the selectivity study recorded with commonly used interferences, and (f) histogram plot of real sample analysis for NO₂⁻ detection using the SBO–GCE.

Fig. 6. (a) CV plot of the bare GCE and SBO–GCE in the absence and presence of 1 mM H₂O₂ at a scan rate of 50 mV s⁻¹, (b) CV plot at different scan rates of 10–50 mV s⁻¹ (inset shows the linear relationship between current vs. scan rate), (c) amperometric i–t curve for the increasing concentration of H₂O₂ 1 μM to 5.847 mM, (d) calibration plot of the SBO–GCE for current vs. concentration of H₂O₂, (e) amperometric plot of the selectivity study recorded with commonly used interferences, and (f) histogram plot of real sample analysis for H₂O₂ detection using the SBO–GCE.