The oxidation of nitrite at boron-doped diamond (BDD) electrode was investigated by use of anodic voltammetry. The voltammetric curves exhibit well-defined anodic peaks, with response that is superior to that obtained with glassy carbon electrodes. The influence of pH, nitrite concentration, and potential sweep rate on the electrode response was thoroughly investigated. The results show that the measurement of the oxidation peak current can be used as the basis for a simple, accurate, rapid method for the determination of <mml:math display="inline"><mml:msubsup><mml:mo>NO</mml:mo><mml:mrow><mml:mn>2</mml:mn></mml:mrow><mml:mrow><mml:mo>−</mml:mo></mml:mrow></mml:msubsup><mml:mo>,</mml:mo></mml:math>NO2−, within a concentration range of 0.002-1 mM. Flow injection analysis with amperometric detection was also examined and improved sensitivity was observed, with analytical useful signals being obtained at 50 nM. The possibility of using anodic voltammetry for the determination of nitrogen oxides (NO and <mml:math display="inline"><mml:msub><mml:mo>NO</mml:mo><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub><mml:mo stretchy="false">)</mml:mo></mml:math>NO2) was also assessed. It is shown that BDD is a very promising electrode material for the detection of nitrogen oxides <mml:math display="inline"><mml:mo stretchy="false">(</mml:mo><mml:mo>NO</mml:mo><mml:mo>,</mml:mo><mml:msub><mml:mo>NO</mml:mo><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub><mml:mo stretchy="false">)</mml:mo></mml:math>(NO,NO2) in gases and the determination of NO in aqueous solution. © 2001 The Electrochemical Society. All rights reserved.

The oxidation of Co(II) at a boron-doped diamond (BDD) electrode was investigated by use of anodic voltammetry. The results shows that this reaction takes place by a mechanism similar to that of cobalt metal oxidation in alkaline media. The voltammetric curves evidence a strong enhancement of the oxygen evolution current in the presence of Co(II). This behavior is consistent with cobalt oxide formation at the diamond electrode surface. Based upon these results, a simple, straightforward method for the production of high activity films on BDD electrode surfaces is demonstrated. The study of the electrochemical behavior in 1 M NaOH shows that the electrodes thus obtained exhibit promising, stable electrocatalytic performance for oxygen evolution, comparing well with those of thermally deposited cobalt electrodes. The use of BDD as a substrate for the electrocatalytic layers allows the deposition of isolated particles or discontinuous films, thus maximizing the utilization of the catalyst by avoiding the need for thick films. © 2003 The Electrochemical Society. All rights reserved.