Powder Microelectrode Modified with Nafion-Os(bpy)₃Â ²⁺ and PVP Composite and Its Catalysis for NO^2- Reduction

Authors

Pei-fang LIU, Dept. of Chem., Wuhan Univ., Wuhan 430072, China
Jia-wei YAN, Dept. of Chem., Wuhan Univ., Wuhan 430072, China

Corresponding Author

Pei-fang LIU

Abstract

The modified powder microelectrode was prepared by etching a Pt (0.1 mm diameter) disk microelectrode and filling in thus formed cavity with Nation-Os(bpy)₃²⁺/PVP composite modified carbon powder. The composite modified powder microelectrode showed cyclic voltammetric behaviors changing with the mole ratio (denoted X) of SO₃^- to Os(bpy)₃²⁺ in Nafion. When X=3, a single pair of current peaks appeared near 0.6V (vs. SCE) due to Os(bpy)₃^2+/3+ redox couple. In contrast, for X=20, a pair of additional current peaks occurred near 0.4V. Both X=3 and X=20 modified powder microelectrodes strongly catalyzed the first electron reduction of nitrite in 0.5 mol/L H₂SO₄. The catalysis was so effective that the steady state polarisation curve showed essentially reversible characteristics with a plateau current density 2.18 mA/cm² and half-wave potentials near 0.55 V. While the electrode with X=3 could catalyze nitrite reduction only to the first electron transfer, the modified powder microelectrode with X=20 could catalyze the second electron transfer, resulting in an additional current wave starting near 0.4 V with a plateau current twice the first one. The plateau current densities obtained with the composite modified powder microelectrodes were much larger than those obtainable with flat electrodes (with or without modification), verifying the idea of advantageous combination of the composite modification and the porous electrode technique. The composite modified powder microelectrodes showed high performance in nitrite detection: sensitivity 814 mAL/cm² mole, linearity 10^-6 ～0.25 mol/L, lower detection limit 10^-6 mol/L; no interference from 0.1 mol/L ascobic acid, Fe³⁺, Fe²⁺ , Mg²⁺, K⁺, NH4⁺, Cl^-,NO₃^- and PO₄^3-.

Keywords

Microelectrode, Modified electrode, Nitrite reduction

DOI Link

https://doi.org/10.61558/2993-074X.1375

Publication Date

2000-05-28

Online Available Date

2000-05-28

Revised Date

2000-05-20

Received Date

2000-01-21

Recommended Citation

Pei-fang LIU, Jia-wei YAN. Powder Microelectrode Modified with Nafion-Os(bpy)₃Â ²⁺ and PVP Composite and Its Catalysis for NO^2- Reduction[J]. Journal of Electrochemistry, 2000 , 6(2): 146-150.
DOI: 10.61558/2993-074X.1375
Available at: https://jelectrochem.xmu.edu.cn/journal/vol6/iss2/2