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Modification of Glassy Carbon Electrode With Single‐Walled Carbon Nanotubes and α‐Silicomolybdate: Application to Sb(III) Detection
Author(s) -
Salimi Abdollah,
Korani Aazam,
Hallaj Rahman,
Khoshnavazi Roshan
Publication year - 2008
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.200804347
Subject(s) - carbon nanotube , polyoxometalate , redox , cyclic voltammetry , electrode , adsorption , glassy carbon , differential pulse voltammetry , materials science , electron transfer , antimony , voltammetry , inorganic chemistry , chemistry , electrochemistry , analytical chemistry (journal) , chemical engineering , nanotechnology , organic chemistry , catalysis , engineering
A simple procedure was developed to prepare a glassy carbon (GC) electrode modified with single‐walled carbon nanotubes (SWCNTs) and polyoxometalate. With immersing SWCNTs modified GC electrode in silicon polyoxomolybdate (α‐SiMo 12 O 40 4− ) solution (direct deposition) for a short period of time (2–10 s) oxoanion adsorbed strongly and irreversibly on SWCNTs. Cyclic voltammograms of the α‐SiMo 12 O 40 4− incorporated‐SWCNTs indicates three well‐defined and reversible redox couples with surface confined characteristic at wide pH range (1–7). The surface coverage ( Γ ) of α‐SiMo 12 O 40 4− immobilized on SWCNTs was 2.14 (±0.11)×10 −9 mol cm −2 indicating high loading ability of SWCNTs for polyoxometalate. The charge transfer rate constant ( k s ) of three redox couples of adsorbed α‐SiMo 12 O 40 4− were 9.20 (±0.20), 8.02 (±0.20), and 3.70 (±0.10) s −1 , respectively, indicate great facilitation of the electron transfer between α‐SiMo 12 O 40 4− and CNTs. In this research the attractive mechanical and electrical characteristics of CNTs and unique properties and reactivity of polyoxometalates were combined. The modified electrode in buffer solution containing Sb(III) shows a new redox system at 0.38 V in pH 1. The voltammetric peak current increased with increasing Sb(III) concentration. The differential pulse voltammetry (DPV) technique was used for detection micromolar concentration of antimony. Furthermore, the interference effects various electroactive compounds on voltammetric response of Sb(III) were negligible. Finally the ability of the modified electrode for antimony detection in real samples was evaluated.