Surface Modification of Diamond Materials and Electrodes

Chemical modification of diamond surfaces is a ripe area for research. Much can be learned about (1) how to control the electrode reaction kinetics and mechanisms at diamond through alterations of the surface chemistry and (2) using such modified surfaces as platforms for sensors and other devices based on the material. 

So far there have been only a few reports concerning the chemical modification of diamond, either insulating or electrically conducting diamond films that would potentially be useful as electrodes. Smentkowski and Yates reported on a facile approach for modifying the hydrogen- 

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Ohtani and coworkers described an approach for covalently attaching a quarternary pyridinium salt to the diamond surface [147]. The reaction strategy first involves introducing surface Cl functional groups by irradiating the surface in the presence of CI2. The chlorinated electrode is then placed in hot pyridine to produce pyridine moieties on the surface. Kim et al. used UV irradiation to convert adsorbed perfluorobutyl iodide on hydrogen-terminated diamond to form covalently attached perfluorobutyl functional groups [148]. 

Hamers and coworkers have shown that the hydrogen-terminated, electrically insulating diamond surface can be chemically modified with functionalized alkenes (e.g., perfluorodecene) [154]. They also showed that it is possible to prepare diamond surfaces terminated with organic molecules containing primary amine and carboxylic acid functional groups. In their approach, chemical functionalization is accomplished with the aid of UV irradiation. The diamond surface, in an enclosed vessel, is exposed to a small volume of the particular organic compound. The solution environ- 

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