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Electrochemical Codeposition of Platinum and Molybdenum Oxides: Formation of Composite Films with Distinct Electrocatalytic Activity for Hydrogen Peroxide Detection
Author(s) -
Kosminsky Luis,
Matos Renato Camargo,
Tabacniks Manfredo H.,
Bertotti Mauro
Publication year - 2003
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.200390092
Subject(s) - platinum , hydrogen peroxide , inorganic chemistry , electrochemistry , molybdenum , chemistry , electrode , electrolyte , polarization (electrochemistry) , reversible hydrogen electrode , hydrogen , oxide , working electrode , catalysis , organic chemistry
The electrochemical properties of gold electrode surfaces modified by molybdenum oxide films intercalated with platinum microparticles have been described. The incorporation of Pt microparticles at the oxide film was characterized by PIXE (particle induced X‐ray emission) spectroscopy. The modified electrode showed electrochemical activity at around −0.5 V in 50 mmol L −1 Na 2 SO 4 supporting electrolyte (pH 3), corresponding to the reduction of protons at platinum sites and further transfer of hydrogen atoms to form reduced molybdenum oxides (bronzes). At 0.1 V, the MoO 3 / Pt electrode showed a better performance for hydrogen peroxide oxidation than on platinized gold electrodes. The solution pH has a marked effect on the voltammetric profile and best responses for hydrogen peroxide were obtained at the 5.0 to 6.0 pH range. The activation of the electrode by polarization at negative potentials was also studied and a mechanism by which more platinum sites are available as a consequence of this process was proposed. Calibration plots for hydrogen peroxide were highly linear ( r =0.9989) in the 0.2 to 1.6 mmol L −1 concentration range, with a relative standard deviation (RSD)<1%.