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This study investigates the underlying mechanisms of hydrogen peroxide (H₂O₂) sensing using a composite material of bismuth oxide and bismuth oxyselenide (Bi2OxSey). The antagonistic effect of tungsten (W)-doping on the electrochemical behavior was also examined. Undoped, 2 mol%, 4 mol%, and 6 mol% W-doped Bi2OxSey nanostructures were synthesized using a one-pot solution phase method involving selenium powder and hydrazine hydrate. W-doping induced a morphological transformation from nanosheets to spherical nanoparticles and amorphization of the bismuth oxyselenide phase. Electrochemical sensing measurements were conducted using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). H₂O₂ detection was achieved over a wide concentration range of 0.02 to 410 µM. In-depth CV analysis revealed the complex interplay of oxidation-reduction processes within the bismuth oxide and Bi2O2Se components of the composite material. W-doping exhibited an antagonistic effect, significantly reducing sensitivity. Among the studied samples, undoped Bi2OxSeγ demonstrated a high sensitivity of 83 μA μM⁻1 cm⁻2 for the CV oxidation peak at 0 V, while 6 mol% W-Bi2OxSey became completely insensitive to H2O2. Interestingly, DPV analysis showed a reversal of sensitivity trends with 2 and 4 mol% W-doping. The applicability of these samples for real-world analysis, including rainwater and urine, was also demonstrated.
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Plasmonic Imaging of Electrochemical Reactions at Individual Prussian Blue Nanoparticles
Prussian blue is an iron-cyanide-based pigment steadily becoming a widely used electrochemical sensor in detecting hydrogen peroxide at low concentration levels. Prussian blue nanoparticles (PBNPs) have been extensively studied using traditional ensemble methods, which only provide averaged information. Investigating PBNPs at a single entity level is paramount for correlating the electrochemical activities to particle structures and will shed light on the major factors governing the catalyst activity of these nanoparticles. Here we report on using plasmonic electrochemical microscopy (PEM) to study the electrochemistry of PBNPs at the individual nanoparticle level. First, two types of PBNPs were synthesized; type I synthesized with double precursors method and type II synthesized with polyvinylpyrrolidone (PVP) assisted single precursor method. Second, both PBNPs types were compared on their electrochemical reduction to form Prussian white, and the effect from the different particle structures was investigated. Type I PBNPs provided better PEM sensitivity and were used to study the catalytic reduction of hydrogen peroxide. Progressively decreasing plasmonic signals with respect to increasing hydrogen peroxide concentration were observed, demonstrating the capability of sensing hydrogen peroxide at a single nanoparticle level utilizing this optical imaging technique.
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- PAR ID:
- 10294796
- Date Published:
- Journal Name:
- Frontiers in Chemistry
- Volume:
- 9
- ISSN:
- 2296-2646
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.3389/fchem.2021.718666
