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oa Iridium/Carbon Films Prepared by MOCVD
OBSERVATIONS AND ELECTROCHEMICAL PROPERTIES RELATING TO OXYGEN ADDITIONS
- Source: Platinum Metals Review, Volume 49, Issue 2, Apr 2005, p. 70 - 76
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- 01 Jan 2005
Abstract
Iridium/carbon (Ir/C) films were prepared by MOCVD using iridium acetylacetonate as the precursor and some electrochemical properties were studied, in particular the effects of oxygen on the carbon content of the Ir/C films. Small additions of oxygen (4 ml min–1) to the source gas drastically decrease the carbon content of the films. Ir grains are formed, up to ~ 3 nm in diameter, in the amorphous carbon. It was found that Ir/C films with higher carbon content have better catalytic performance – for measuring the oxygen concentration – than Ir/C films with lower carbon content. The Ir/C films were used as electrodes in an oxygen concentration cell, and the sensitivity of the cell to oxygen was recorded. The Nernstian electromotive force of the cell is almost the same as that of a similar type of commercial oxygen concentration sensor from Bosch, but the response time is faster.