Photoelectrochemical sensing of hydrogen peroxide at zero working potential using a fluorine-doped tin oxide electrode modified with BiVO4 microrods

The authors describe a highly efficient photoelectrochemical (PEC) scheme for the determination of hydrogen peroxide (H2O2). BiVO4 microrods were hydrothermally synthesized and deposited on fluorine - doped tin oxide (FTO) glass which acts as the working electrode. Scanning electron microscopy, X-ray powder diffraction and Raman spectroscopy were utilized for the characterization of the microrods. On irradiation with visible light, the holes generated in the microrods are capturing electrons from H2O2 to produce a photocurrent at an operating potential of 0 V vs. Ag/AgCl. Under optimal conditions, the photocurrent increases with the concentration of H2O2 in the range from 50 μmol·L−1 to 1.5 mmol·L−1, and the limit of detection is 8.5 μmol·L−1 (at 3σ). A repeatability and intermediate precision of ≤6.6% was accomplished at H2O2 levels of 0.1, 0.5 and 1.0 mmol·L−1. The method was applied to the determination of H2O2 in spiked sterilized milk samples and gave satisfactory results. As the method works at zero potential, the photocurrent can be measured with simple instrumentation such as digital multimeters, and this will enable expensive electrochemical workstations to be replaced in future.